Provision of data via PDS to ONS

The Data Recipient agrees to process the Data only for the following purposes, as agreed with NHS England:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act (SRSA) 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board carries out this function. Within ONS, the Health, Population and Methods Group are responsible for providing key data on the population of the United Kingdom and are comprised of a number of divisions that undertake demographic analysis in, for example, migration, fertility, mortality, life expectancy, ageing and families. These analyses are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to, from time to time, collect and publish any statistical information relating to the number and condition of the population in the interval between one census and another and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the SRSA 2007.

ONS rely on the following lawful bases under the General Data Protection Regulation for processing personal data including special categories of personal data:

• GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

• GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom's National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business and enable better decisions to be made. Using administrative data such as Personal Demographics Service (PDS) allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census and population statistics – more detailed justifications are outlined in greater depth below. Proportionality is considered by business areas who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address, and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out under this Agreement will be requested and processed.

Amazon Web Services provide IT hosting services to ONS and will store the data as contracted by ONS as a processor.

The Integrated Data Service (IDS) is a cloud-based Trusted Research Environment (TRE) where analysts process data for the purposes listed in this Agreement.

Google UK Limited provide IT hosting services to ONS for the IDS and will store the data as contracted by ONS as a processor.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by employees of ONS or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions, thus ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading 'Data Environment'.

Population Statistics

NHS England previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. PDS stocks are also to be used in place of the now defunct PR data to produce small area population estimates at Lower Layer Super Output Area (LSOA), Middle Layer Super Output Area (MSOA), Output Area (OA), ward, Clinical Commissioning Group (CCG), parliamentary constituencies, and National Park levels. With the loss of the NHAIS posting information, the PDS will be used to produce estimates of internal migration - therefore more detailed address information is required from weekly PDS updates so that the address data can be run through ONS’ Address Index Matching System (AIMS). The PDS will also help ONS to understand how migrants interact with services.

Internal migration estimates are national statistics and are a key component in population estimates, projections and national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, for estimating the local authority distribution of international migrants component of change mid-year estimates and small area population estimates within England and Wales and for estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students and data from HMRC and DWP.

Census and Data Collection Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

• Population and housing estimates: counts of the population by age and sex, and the number of housing units.

• Population structures: households, families and household relationships.

• Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. The Census also provides a precise estimate of the UK population. Any statistics produced that relate to the general population are understood by comparing against this estimate. Mortality rates, household income, disease prevalence, employment rates, vaccination rates and more all rely on an accurate population estimate. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended to the Board of the UK Statistics Authority that the future provision of population statistics and the next census should be through:

"An online census of all households and communal establishments in England and Wales in 2021 recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses."

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

'Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA's plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.' - Government's response to the National Statistician's recommendation, 18 July 2014.

The Census and Data Collection Transformation Programme (CDCTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether, in ONS' view, the Government's ambition can be realised. To that end, ONS has committed to publishing an annual assessment of progress towards the Government's ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. Since 2015 ONS has produced annual Admin Based Population Estimates (ABPEs), formerly known as Statistical Population Datasets (SPDs), based on linking multiple administrative datasets (including NHS Patient Registration (PR) Data, Department for Work and Pensions (DWP)/Her Majesty’s Revenue and Customs (HMRC), Customer Information System data and higher education data).

No one dataset in its' own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics by helping to address issues relating to definitional differences between administrative data and population definitions and time lags.

To enable ONS’s Administrative Based Census Project, including placing administrative data at the core of migration statistics, using ‘activity’ and characteristics data from PDS ONS’s Administrative Based Census Project (ABC) is assessing whether the Government’s ambition that ‘censuses after 2021 be conducted using other sources of data’ can be realised. ONS aims to replicate the type of information collected through a census by using administrative data already held by government, supplemented by surveys. This can then be compared with the data collected by the 2021 census itself. This will allow ONS to determine whether this alternative approach can meet users’ needs. As part of this work ONS will be producing a non-disclosive, de-identified Administrative Based Census (ABC) dataset for research use. This will be a heavily derived data product containing only the age, sex and Lower Layer Super Output Area (LSOA) for records included within the ABC. This ABC output dataset will be produced through amalgamating multiple administrative data sources (including NHS Personal Demographics Service, Hospital Episode Statistics, Emergency Care Dataset plus a multitude of data from other sources) to generate a de-identified record for every usual resident in England and Wales and help estimate the population at a local level. This de-identified, non-disclosive ONS product (the ABC) will be made available for approved / accredited research use within ONS operated Trusted Research Environments (TREs).

There is no common identifier that can be used to link individuals' records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, full name, addresses and postcodes) to link the datasets and establish the aforementioned ABPEs. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data was needed to support the 2021 Census and continues to be needed to provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021, whilst also ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other administrative data sources, however no clinical data is being requested. Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce ABPEs and allow analyses to meet the 2023 recommendation of the future of the Census.

Census 2021 Quality Assurance

ONS conducted the Census for England and Wales on 21st March 2021, which is one of the most important and highest profile National Statistical productions. The Census will provide a decennial picture of the size and state of the population and will feed directly into funding and service provision policies. Although the Census is mandatory, not everyone is captured. Data collected in the Census can be compared with data from the PDS to ensure it is reliable and will allow ONS to gather data needed to inform work around the Census. This will help ONS to quality assure Census returns and prepare outputs.

International Migration

The Centre for International Migration is leading on work to transform international migration statistics through the development of administrative data-based migration estimates (ABMEs) that will better meet user needs for timely and accurate statistics on this topic area. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee's report and government response.

The PDS data forms an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved international migration estimates at local level. Improved statistics, at a more granular level, may enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data hopes to allow the centre to:

• Compare signs of the arrival, activity and departures of international migrants by linking PDS to other public sector datasets.

• Use knowledge and information from PDS to inform ABMEs and modelled estimates of international migration.

• Provide analysis and research into how international migrants interact with the health system and the impact of international migration on the health sector, including via linkage to other public sector datasets.

ONS use PR/PDS data to carry out population level analysis. PDS data includes address and date of birth variables which can be used as analytical variables for population groups for example. This may facilitate the creation of location-based variables or flags for analysis. By using the PDS data to assign 'location-based variables' ONS can ensure population indicators collected in other linked data sources such as the Census are updated to reflect the most recent living situation of the population of interest. For example, between the 10-yearly census information on the size and condition of the population living in deprived areas, information on small geographic locations or communal establishments (such as care homes) are not readily available. PDS data can be used to identify and quantify the size of these populations. The PDS data can also be used alongside other data sources such as Provider Information Returns data held by the Care Quality Commission to identify and better understand the characteristics of the population receiving social care.

To note, ONS analysts do not actually scrutinize individual rows of data, rather they run models on large scale datasets with millions of rows, and then scrutinize the outputs and aggregate results. Once aggregated ONS analysts will never try to identify or re-identify individuals.

Survey Sampling Purposes

ONS require the use of administrative data to improve sampling frames for survey collections. The PDS data will be used to increase sample sizes, improve representativeness and ensure survey response rates remain high enough to produce statistics and analysis with actionable insights. Examples of surveys that will be enhanced through the use of PDS data include but are not limited to:

Health Insight Survey

The Health Insight Survey is an online questionnaire designed to give patients the opportunity to offer regular feedback about their experiences of the NHS to ensure the NHS can offer the best possible service. The survey asks people about their experiences of accessing care at their local GP practice and experience of other NHS services in England.

Participants consist of people who took part in the Coronavirus (COVID-19) Infection Survey (CIS) and agreed to be approached about other ethically approved research studies. To improve the representativeness of the sample, demographic and geographic data available in PDS will be used to identify and invite new participants to complete the survey.

Children’s Crime Survey

The current Children’s Crime Survey for England and Wales (CCSEW) is a face-to-face survey of children aged 10 to 15 years. One child is invited to take part in households where an individual aged 16 years or over has taken part in the adult Crime Survey for England and Wales (CSEW). It is one of few continuous, nationally representative surveys of children and provides important information on the prevalence and nature of crime and other harmful experiences among children.

Unfortunately, the ability to achieve the key outcome has been severely restricted in recent years by declining response rates to face-to-face interviews. In response to evolving user needs and changes in respondent behaviour following the COVID-19 pandemic, there has been a need for us to review how the CCSEW operates to ensure we can continue to produce timely and quality statistics which meet the needs of users. The CCSEW is therefore being redesigned to transform it to an online mode of data collection, and decouple it from the CSEW through sampling children directly from administrative data sources.

Safety During Childhood Survey

The Safety During Childhood Survey has been designed as two surveys – one which is conducted in school and one conducted online. The online component is for people aged 16 to 25. This is an essential part of filling the evidence gap for child abuse. It ensures we can develop a prevalence estimate for 12-17 year olds (and not just those up to age 16 in school). It also allows us to produce estimates for young adult (18-25) who are close to childhood age but with a perspective of what happened to them that may well be different to under 18s. In order to target our online sample, we need a sampling frame which contains date of birth.

The outputs expected from this work include statistics, statistical reports, presentations, methodology papers and analyses. All outputs are produced in order to meet ONS’ role to produce statistics for the public good. Should outputs contain any data, this data will be aggregated with small numbers supressed.

Any official statistics produced will be published so that they are publicly available - for example on the ONS website, in statistical bulletins, analysis articles or on data dashboards.

Projects focused on new topics or new data sources will include exploration of the feasibility of using and/or linking the data. They will also quality assess the data and linkage prior to full development of analyses and publication of statistics. Briefings for technical/expert audiences or methodology reports may be written for internal use in the development and assessment of new data sources and analysis. These reports will be published alongside experimental statistics or official statistics on the ONS website or in peer-reviewed journals as appropriate.

All ONS statistical teams engage regularly with users and will seek to provide frequent updates on the production of official statistics through regular stakeholder conversations, presentations and events.

ONS have a publishing strategy and team which supports analytical teams in developing different outputs to suit a range of different audiences. ONS also has active communications, media and social media teams to promote dissemination of statistics and enable outputs to reach a wide-ranging audience.

Census and Data Collection Transformation Programme (CDCTP)

ONS has committed to publishing regular annual Administrative Data Research Outputs (ABPEs) on the population, including estimates on the size of the population (produced using administrative data).

The aims of these research outputs are to:

- Update users on the progress made through administrative data and to seek feedback from users - the aim being to improve the methods used.

- Aid the process of working with data suppliers to improve data quality for statistical purposes.

ONS has already developed ABPEs in both method and content in the run up to the 2021 Census and plan to compare the ABPEs with results from the 2021 Census. ONS will also expand on the range of topics and granularity of information published each year.

ONS recognise the need for continued development of their methodology. Future releases will therefore include further outputs based on future methodology developments which hope to allow for user feedback, newly available data and alternative techniques to facilitate the production of population statistics.

The research on the feasibility of producing administrative, data-based characteristics estimates that ONS should be able to provide evidence to feed into the 2023 recommendation on the future of the Census. ONS aim to produce research outputs on the progress they have made on the feasibility research they’re conducting on user feedback. The outputs will be in the form of aggregate statistics, with statistics disclosure rules applied where necessary.

Population and Migration

Main publication dates are as follows:

Internal migration - Annually – June

Internal migration statistics are published at local authority level by age and sex. They are used widely by local authorities and academics to, for example, feed into alternative population projections models and subsequent resource allocation planning.

Mid-year estimates - Annually - June, with lower-level geography releases after this until Small Area Population Estimates are released in November.

National Population projections - normally published at the end of October. Releases have traditionally been produced bi-annually. Following the release of the national projections, there are now sub-national releases between national releases.

Internal migration estimates form a key component of population estimates and population projections, which are of important use in the UK. Estimates are used by central government, local government and health authorities to support resource allocation as well as forming a fundamental basis for other statistics across government which feed into policy decisions.

Projections are used to determine the future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services needed - for example a hospital may use projections to determine whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Health and Mortality Analysis

Specific outputs will include published aggregate statistics on the number, characteristics and condition of population groups such as the social care, care home and disabled population (providing more detail on specific impairments). ONS will produce mortality, morbidity and life expectancy statistics by protected characteristics such as ethnicity, disability and specific age groups.

Admin Based Census (ABC)

As part of ONS' work on producing more accurate statistics on the population at a local level through administrative data, a non-disclosive, de-identified Administrative Based Census (ABC) dataset will be created for research use. This will be a heavily derived data product containing only the age, sex and Lower Layer Super Output Area (LSOA) for records included within the ABC. This ABC output dataset will be produced through amalgamating multiple administrative data sources (including NHS Personal Demographics Service, Hospital Episode Statistics, Emergency Care Dataset plus a multitude of data from other sources) to generate a de-identified record for every usual resident in England and Wales and help estimate the population at a local level. This de-identified, non-disclosive ONS product (the ABC) will be made available for approved / accredited research use within ONS operated Trusted Research Environments (TREs).

The data that are being used for sampling purposes will enable the sharing of analysis and publishing of statistics, such as but not limited to:

Health Insight Survey

ONS and NHS England are entering into a Memorandum of Understanding to set out the basis on which they will collaborate with each other on the provision of the Health Insight Survey. The objective of this collaboration necessitate the use of PDS data to enhance the sample for the survey, namely:

- To boost the sample to seek to a) counteract attrition, b) increase the number of participants in groups that are currently under-represented including younger and people from ethnic minorities, and c) achieve a sample size consistently large enough within the 22 Primary Care Network (PCN) test sites to provide actionable insight

This will enable ONS to make available to NHS England insight into patient experience of health services based on HIS, including with regards to inequalities, and at regional, ICB-level and PCN level.

Children’s Crime Survey and Safety During Childhood Survey

Redesigned CCSEW ready to run live at 15K by September 2025, (replacing the existing face-to-face Children's CSEW which ends in March 2025. This will enable continuation of the regular collection of much needed nationally representative data on the prevalence and nature of crime and other harmful experiences among children in England and Wales. Utilising PDS data for sampling purposes will enable ONS to enhance this children’s data collection through improving flexibility, sustainability and efficiency of survey delivery. It will allow an increased sample size to improve quality and use of the data, and will enable greater demographic and intersectional breakdowns to better meet user needs. It will also provide opportunities for expanding the sample as required in the future. Ultimately the redesigned survey will improve official statistics on children’s victimisation and other crime-related topics to enable evidence-informed government decisions and help with the framing of policy and legislative initiatives that support and protect children, aligning with two of the new Government missions: Breaking Down the Barriers to Opportunity and Making Britain’s Streets Safe. These statistics will also be important for informing and monitoring the impact of policy recommendations for improving children’s safety in the community and online, such as those highlighted in the Children's Commissioners' Big Answer.

https://labour.org.uk/wp-content/uploads/2023/07/Mission-breaking-down-barriers.pdf

https://labour.org.uk/wp-content/uploads/2023/03/Mission-Safety.pdf

https://www.childrenscommissioner.gov.uk/the-big-answer/

The Safety During Childhood Survey has two expected key outputs:

- A pilot of the online 16-25 survey is due to be completed in 2025 for which a sample frame is required. This will be part of evaluating the operational design of the survey.

- The full survey is planned for 2026. It is from that survey which we will produce national estimates of child abuse experienced by 12-17 year olds and 18-25 year olds.

All of the above outputs will feed into the realisation of the benefit ES1: Better informed decisions that better reflect experiences in all the UK – at a national and local level, for government departments, local governments and regional agencies, this will generate approximately £32.48M.

It is hoped within the next year to two years, the Safety During Childhood Survey and the redesigned Children’s Crime Survey will become fully integrated surveys within the ONS contributing towards various government statistics to drive crime policy forward.

PDS is a key data source for the admin-based population estimates (ABPEs) produced using the Dynamic Population model (DPM). The DPM balances input data on population (stocks) at specific points in time with the components of population change (flows of births, deaths, and migrants) over time. PDS data is used within the population stock data and migrant estimates (internal and international).

We published provisional mid-2023 ABPEs for local authorities in England and Wales in December 2023 and updated mid-2011 to mid-2023 ABPEs in July 2024. Commentary for our July release is provided in our Population estimates for England and Wales: mid-2023 bulletin alongside the latest official estimates (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/dynamicpopulationmodelimprovementstodatasourcesandmethodology/localauthoritiesinenglandandwalesmid2011tomid2023). This allows users to compare the ABPEs with official population estimates.

The ABPEs are currently official statistics in development while we refine our methods and the data sources used to estimate the usual resident population. We are aiming for our APBEs to become the official mid-year population estimates in 2025. This is dependent on the use of PDS data.

Population estimates have a wide range of uses across government, including the health sector, in terms of resource allocation, policy making and service planning. Population estimates are also used as a denominator for rates relating to health such as mortality rates and fertility rates.

The PDS is also a key data source used in the Refugee Integration Outcomes (RIO) project. The RIO project links Home Office data on refugees granted asylum and individuals who came to the UK under a resettlement scheme with data from the PDS, Home Office Borders and Immigration (HOBI), Census 2021 and several other administrative data sources, to create an anonymised analytical dataset covering health, housing, economic, education and social outcomes. The current iteration of RIO includes refugees resettled in England and Wales under the Vulnerable Persons Resettlement Scheme (VPRS) and Vulnerable Children’s Resettlement Scheme (VCRS) and those granted asylum between 2015 and 2020, with data for additional cohorts currently being linked.

Refugee integration is a challenging and high-profile policy area, with refugee status most often invisible in analytical datasets. The RIO project aims to fill this evidence gap and is now providing unique insights into social and economic integration outcomes through the evaluation of refugee integration programmes. We published early analysis from RIO in June 2023, which provided new insights into health and housing outcomes for resettled refugees using linked Census 2021 data, alongside a report on linkage quality. This analysis would not have been possible without PDS stocks data. Linking data is the optimal way of generating new insights on refugee integration outcomes, both in terms of coverage and quality. The value of data already collected is maximised and the burden involved in collecting data directly from refugees or support providers is minimised.

The Data Recipient agrees to process the Data only for the following purposes, as agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act (SRSA) 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board carries out this function. Within ONS, the Health, Population and Methods Group are responsible for providing key data on the population of the United Kingdom and are comprised of a number of divisions that undertake demographic analysis in, for example, migration, fertility, mortality, life expectancy, ageing and families. These analyses are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to, from time to time, collect and publish any statistical information relating to the number and condition of the population in the interval between one census and another and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the SRSA 2007.

ONS rely on the following lawful bases under the General Data Protection Regulation for processing personal data including special categories of personal data:

• GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

• GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom's National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business and enable better decisions to be made. Using administrative data such as Personal Demographics Service (PDS) allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census and population statistics – more detailed justifications are outlined in greater depth below. Proportionality is considered by business areas who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address, and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out under this Agreement will be requested and processed.

Amazon Web Services provide IT hosting services to ONS and will store the data as contracted by ONS as a processor.

The Integrated Data Service (IDS) is a cloud-based Trusted Research Environment (TRE) where analysts process data for the purposes listed in this Agreement.

Google UK Limited provide IT hosting services to ONS for the IDS and will store the data as contracted by ONS as a processor.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by employees of ONS or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions, thus ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading 'Data Environment'.

Population Statistics

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. PDS stocks are also to be used in place of the now defunct PR data to produce small area population estimates at Lower Layer Super Output Area (LSOA), Middle Layer Super Output Area (MSOA), Output Area (OA), ward, Clinical Commissioning Group (CCG), parliamentary constituencies, and National Park levels. With the loss of the NHAIS posting information, the PDS will be used to produce estimates of internal migration - therefore more detailed address information is required from weekly PDS updates so that the address data can be run through ONS’ Address Index Matching System (AIMS). The PDS will also help ONS to understand how migrants interact with services.

Internal migration estimates are national statistics and are a key component in population estimates, projections and national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, for estimating the local authority distribution of international migrants component of change mid-year estimates and small area population estimates within England and Wales and for estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students and data from HMRC and DWP.

Census and Data Collection Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

• Population and housing estimates: counts of the population by age and sex, and the number of housing units.

• Population structures: households, families and household relationships.

• Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. The Census also provides a precise estimate of the UK population. Any statistics produced that relate to the general population are understood by comparing against this estimate. Mortality rates, household income, disease prevalence, employment rates, vaccination rates and more all rely on an accurate population estimate. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended to the Board of the UK Statistics Authority that the future provision of population statistics and the next census should be through:

"An online census of all households and communal establishments in England and Wales in 2021 recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses."

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

'Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA's plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.' - Government's response to the National Statistician's recommendation, 18 July 2014.

The Census and Data Collection Transformation Programme (CDCTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether, in ONS' view, the Government's ambition can be realised. To that end, ONS has committed to publishing an annual assessment of progress towards the Government's ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. Since 2015 ONS has produced annual Admin Based Population Estimates (ABPEs), formerly known as Statistical Population Datasets (SPDs), based on linking multiple administrative datasets (including NHS Patient Registration (PR) Data, Department for Work and Pensions (DWP)/Her Majesty’s Revenue and Customs (HMRC), Customer Information System data and higher education data).

No one dataset in its' own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics by helping to address issues relating to definitional differences between administrative data and population definitions and time lags.

To enable ONS’s Administrative Based Census Project, including placing administrative data at the core of migration statistics, using ‘activity’ and characteristics data from PDS ONS’s Administrative Based Census Project (ABC) is assessing whether the Government’s ambition that ‘censuses after 2021 be conducted using other sources of data’ can be realised. ONS aims to replicate the type of information collected through a census by using administrative data already held by government, supplemented by surveys. This can then be compared with the data collected by the 2021 census itself. This will allow ONS to determine whether this alternative approach can meet users’ needs. As part of this work ONS will be producing a non-disclosive, de-identified Administrative Based Census (ABC) dataset for research use. This will be a heavily derived data product containing only the age, sex and Lower Layer Super Output Area (LSOA) for records included within the ABC. This ABC output dataset will be produced through amalgamating multiple administrative data sources (including NHS Personal Demographics Service, Hospital Episode Statistics, Emergency Care Dataset plus a multitude of data from other sources) to generate a de-identified record for every usual resident in England and Wales and help estimate the population at a local level. This de-identified, non-disclosive ONS product (the ABC) will be made available for approved / accredited research use within ONS operated Trusted Research Environments (TREs).

There is no common identifier that can be used to link individuals' records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, full name, addresses and postcodes) to link the datasets and establish the aforementioned ABPEs. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data was needed to support the 2021 Census and continues to be needed to provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021, whilst also ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other administrative data sources, however no clinical data is being requested. Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce ABPEs and allow analyses to meet the 2023 recommendation of the future of the Census.

Census 2021 Quality Assurance

ONS conducted the Census for England and Wales on 21st March 2021, which is one of the most important and highest profile National Statistical productions. The Census will provide a decennial picture of the size and state of the population and will feed directly into funding and service provision policies. Although the Census is mandatory, not everyone is captured. Data collected in the Census can be compared with data from the PDS to ensure it is reliable and will allow ONS to gather data needed to inform work around the Census. This will help ONS to quality assure Census returns and prepare outputs.

International Migration

The Centre for International Migration is leading on work to transform international migration statistics through the development of administrative data-based migration estimates (ABMEs) that will better meet user needs for timely and accurate statistics on this topic area. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee's report and government response.

The PDS data forms an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved international migration estimates at local level. Improved statistics, at a more granular level, may enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data hopes to allow the centre to:

• Compare signs of the arrival, activity and departures of international migrants by linking PDS to other public sector datasets.

• Use knowledge and information from PDS to inform ABMEs and modelled estimates of international migration.

• Provide analysis and research into how international migrants interact with the health system and the impact of international migration on the health sector, including via linkage to other public sector datasets.

ONS use PR/PDS data to carry out population level analysis. PDS data includes address and date of birth variables which can be used as analytical variables for population groups for example. This may facilitate the creation of location-based variables or flags for analysis. By using the PDS data to assign 'location-based variables' ONS can ensure population indicators collected in other linked data sources such as the Census are updated to reflect the most recent living situation of the population of interest. For example, between the 10-yearly census information on the size and condition of the population living in deprived areas, information on small geographic locations or communal establishments (such as care homes) are not readily available. PDS data can be used to identify and quantify the size of these populations. The PDS data can also be used alongside other data sources such as Provider Information Returns data held by the Care Quality Commission to identify and better understand the characteristics of the population receiving social care.

To note, ONS analysts do not actually scrutinize individual rows of data, rather they run models on large scale datasets with millions of rows, and then scrutinize the outputs and aggregate results. Once aggregated ONS analysts will never try to identify or re-identify individuals.

The outputs expected from this work include statistics, statistical reports, presentations, methodology papers and analyses. All outputs are produced in order to meet ONS’ role to produce statistics for the public good. Should outputs contain any data, this data will be aggregated with small numbers supressed.

Any official statistics produced will be published so that they are publicly available - for example on the ONS website, in statistical bulletins, analysis articles or on data dashboards.

Projects focused on new topics or new data sources will include exploration of the feasibility of using and/or linking the data. They will also quality assess the data and linkage prior to full development of analyses and publication of statistics. Briefings for technical/expert audiences or methodology reports may be written for internal use in the development and assessment of new data sources and analysis. These reports will be published alongside experimental statistics or official statistics on the ONS website or in peer-reviewed journals as appropriate.

All ONS statistical teams engage regularly with users and will seek to provide frequent updates on the production of official statistics through regular stakeholder conversations, presentations and events.

ONS have a publishing strategy and team which supports analytical teams in developing different outputs to suit a range of different audiences. ONS also has active communications, media and social media teams to promote dissemination of statistics and enable outputs to reach a wide-ranging audience.

Census and Data Collection Transformation Programme (CDCTP)

ONS has committed to publishing regular annual Administrative Data Research Outputs (ABPEs) on the population, including estimates on the size of the population (produced using administrative data).

The aims of these research outputs are to:

- Update users on the progress made through administrative data and to seek feedback from users - the aim being to improve the methods used.

- Aid the process of working with data suppliers to improve data quality for statistical purposes.

ONS has already developed ABPEs in both method and content in the run up to the 2021 Census and plan to compare the ABPEs with results from the 2021 Census. ONS will also expand on the range of topics and granularity of information published each year.

ONS recognise the need for continued development of their methodology. Future releases will therefore include further outputs based on future methodology developments which hope to allow for user feedback, newly available data and alternative techniques to facilitate the production of population statistics.

The research on the feasibility of producing administrative, data-based characteristics estimates that ONS should be able to provide evidence to feed into the 2023 recommendation on the future of the Census. ONS aim to produce research outputs on the progress they have made on the feasibility research they’re conducting on user feedback. The outputs will be in the form of aggregate statistics, with statistics disclosure rules applied where necessary.

Population and Migration

Main publication dates are as follows:

Internal migration - Annually – June

Internal migration statistics are published at local authority level by age and sex. They are used widely by local authorities and academics to, for example, feed into alternative population projections models and subsequent resource allocation planning.

Mid-year estimates - Annually - June, with lower-level geography releases after this until Small Area Population Estimates are released in November.

National Population projections - normally published at the end of October. Releases have traditionally been produced bi-annually. Following the release of the national projections, there are now sub-national releases between national releases.

Internal migration estimates form a key component of population estimates and population projections, which are of important use in the UK. Estimates are used by central government, local government and health authorities to support resource allocation as well as forming a fundamental basis for other statistics across government which feed into policy decisions.

Projections are used to determine the future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services needed - for example a hospital may use projections to determine whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Health and Mortality Analysis

Specific outputs will include published aggregate statistics on the number, characteristics and condition of population groups such as the social care, care home and disabled population (providing more detail on specific impairments). ONS will produce mortality, morbidity and life expectancy statistics by protected characteristics such as ethnicity, disability and specific age groups.

Admin Based Census (ABC)

As part of ONS' work on producing more accurate statistics on the population at a local level through administrative data, a non-disclosive, de-identified Administrative Based Census (ABC) dataset will be created for research use. This will be a heavily derived data product containing only the age, sex and Lower Layer Super Output Area (LSOA) for records included within the ABC. This ABC output dataset will be produced through amalgamating multiple administrative data sources (including NHS Personal Demographics Service, Hospital Episode Statistics, Emergency Care Dataset plus a multitude of data from other sources) to generate a de-identified record for every usual resident in England and Wales and help estimate the population at a local level. This de-identified, non-disclosive ONS product (the ABC) will be made available for approved / accredited research use within ONS operated Trusted Research Environments (TREs).

PDS is a key data source for the admin-based population estimates (ABPEs) produced using the Dynamic Population model (DPM). The DPM balances input data on population (stocks) at specific points in time with the components of population change (flows of births, deaths, and migrants) over time. PDS data is used within the population stock data and migrant estimates (internal and international).

We published provisional mid-2023 ABPEs for local authorities in England and Wales in December 2023 and updated mid-2011 to mid-2023 ABPEs in July 2024. Commentary for our July release is provided in our Population estimates for England and Wales: mid-2023 bulletin alongside the latest official estimates (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/dynamicpopulationmodelimprovementstodatasourcesandmethodology/localauthoritiesinenglandandwalesmid2011tomid2023). This allows users to compare the ABPEs with official population estimates.

The ABPEs are currently official statistics in development while we refine our methods and the data sources used to estimate the usual resident population. We are aiming for our APBEs to become the official mid-year population estimates in 2025. This is dependent on the use of PDS data.

Population estimates have a wide range of uses across government, including the health sector, in terms of resource allocation, policy making and service planning. Population estimates are also used as a denominator for rates relating to health such as mortality rates and fertility rates.

The PDS is also a key data source used in the Refugee Integration Outcomes (RIO) project. The RIO project links Home Office data on refugees granted asylum and individuals who came to the UK under a resettlement scheme with data from the PDS, Home Office Borders and Immigration (HOBI), Census 2021 and several other administrative data sources, to create an anonymised analytical dataset covering health, housing, economic, education and social outcomes. The current iteration of RIO includes refugees resettled in England and Wales under the Vulnerable Persons Resettlement Scheme (VPRS) and Vulnerable Children’s Resettlement Scheme (VCRS) and those granted asylum between 2015 and 2020, with data for additional cohorts currently being linked.

Refugee integration is a challenging and high-profile policy area, with refugee status most often invisible in analytical datasets. The RIO project aims to fill this evidence gap and is now providing unique insights into social and economic integration outcomes through the evaluation of refugee integration programmes. We published early analysis from RIO in June 2023, which provided new insights into health and housing outcomes for resettled refugees using linked Census 2021 data, alongside a report on linkage quality. This analysis would not have been possible without PDS stocks data. Linking data is the optimal way of generating new insights on refugee integration outcomes, both in terms of coverage and quality. The value of data already collected is maximised and the burden involved in collecting data directly from refugees or support providers is minimised.

The Data Recipient agrees to process the Data only for the following purposes, as agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act (SRSA) 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board carries out this function. Within ONS, the Health, Population and Methods Group are responsible for providing key data on the population of the United Kingdom and are comprised of a number of divisions that undertake demographic analysis in, for example, migration, fertility, mortality, life expectancy, ageing and families. These analyses are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to, from time to time, collect and publish any statistical information relating to the number and condition of the population in the interval between one census and another and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the SRSA 2007.

ONS rely on the following lawful bases under the General Data Protection Regulation for processing personal data including special categories of personal data:

• GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

• GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom's National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business and enable better decisions to be made. Using administrative data such as Personal Demographics Service (PDS) allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census and population statistics – more detailed justifications are outlined in greater depth below. Proportionality is considered by business areas who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address, and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out under this Agreement will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by employees of ONS or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions, thus ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading 'Data Environment'.

Population Statistics

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. PDS stocks are also to be used in place of the now defunct PR data to produce small area population estimates at Lower Layer Super Output Area (LSOA), Middle Layer Super Output Area (MSOA), Output Area (OA), ward, Clinical Commissioning Group (CCG), parliamentary constituencies, and National Park levels. With the loss of the NHAIS posting information, the PDS will be used to produce estimates of internal migration - therefore more detailed address information is required from weekly PDS updates so that the address data can be run through ONS’ Address Index Matching System (AIMS). The PDS will also help ONS to understand how migrants interact with services.

Internal migration estimates are national statistics and are a key component in population estimates, projections and national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, for estimating the local authority distribution of international migrants component of change mid-year estimates and small area population estimates within England and Wales and for estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students and data from HMRC and DWP.

Census and Data Collection Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

• Population and housing estimates: counts of the population by age and sex, and the number of housing units.

• Population structures: households, families and household relationships.

• Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. The Census also provides a precise estimate of the UK population. Any statistics produced that relate to the general population are understood by comparing against this estimate. Mortality rates, household income, disease prevalence, employment rates, vaccination rates and more all rely on an accurate population estimate. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended to the Board of the UK Statistics Authority that the future provision of population statistics and the next census should be through:

"An online census of all households and communal establishments in England and Wales in 2021 recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses."

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

'Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA's plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.' - Government's response to the National Statistician's recommendation, 18 July 2014.

The Census and Data Collection Transformation Programme (CDCTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether, in ONS' view, the Government's ambition can be realised. To that end, ONS has committed to publishing an annual assessment of progress towards the Government's ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. Since 2015 ONS has produced annual Admin Based Population Estimates (ABPEs), formerly known as Statistical Population Datasets (SPDs), based on linking multiple administrative datasets (including NHS Patient Registration (PR) Data, Department for Work and Pensions (DWP)/Her Majesty’s Revenue and Customs (HMRC), Customer Information System data and higher education data).

No one dataset in its' own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics by helping to address issues relating to definitional differences between administrative data and population definitions and time lags.

There is no common identifier that can be used to link individuals' records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, full name, addresses and postcodes) to link the datasets and establish the aforementioned ABPEs. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data was needed to support the 2021 Census and continues to be needed to provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021, whilst also ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other administrative data sources, however no clinical data is being requested. Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce ABPEs and allow analyses to meet the 2023 recommendation of the future of the Census.

Census 2021 Quality Assurance

ONS conducted the Census for England and Wales on 21st March 2021, which is one of the most important and highest profile National Statistical productions. The Census will provide a decennial picture of the size and state of the population and will feed directly into funding and service provision policies. Although the Census is mandatory, not everyone is captured. Data collected in the Census can be compared with data from the PDS to ensure it is reliable and will allow ONS to gather data needed to inform work around the Census. This will help ONS to quality assure Census returns and prepare outputs.

International Migration

The Centre for International Migration is leading on work to transform international migration statistics through the development of administrative data-based migration estimates (ABMEs) that will better meet user needs for timely and accurate statistics on this topic area. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee's report and government response.

The PDS data forms an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved international migration estimates at local level. Improved statistics, at a more granular level, may enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data hopes to allow the centre to:

• Compare signs of the arrival, activity and departures of international migrants by linking PDS to other public sector datasets.

• Use knowledge and information from PDS to inform ABMEs and modelled estimates of international migration.

• Provide analysis and research into how international migrants interact with the health system and the impact of international migration on the health sector, including via linkage to other public sector datasets.

ONS use PR/PDS data to carry out population level analysis. PDS data includes address and date of birth variables which can be used as analytical variables for population groups for example. This may facilitate the creation of location-based variables or flags for analysis. By using the PDS data to assign 'location-based variables' ONS can ensure population indicators collected in other linked data sources such as the Census are updated to reflect the most recent living situation of the population of interest. For example, between the 10-yearly census information on the size and condition of the population living in deprived areas, information on small geographic locations or communal establishments (such as care homes) are not readily available. PDS data can be used to identify and quantify the size of these populations. The PDS data can also be used alongside other data sources such as Provider Information Returns data held by the Care Quality Commission to identify and better understand the characteristics of the population receiving social care.

To note, ONS analysts do not actually scrutinize individual rows of data, rather they run models on large scale datasets with millions of rows, and then scrutinize the outputs and aggregate results. Once aggregated ONS analysts will never try to identify or re-identify individuals.

The outputs expected from this work include statistics, statistical reports, presentations, methodology papers and analyses. All outputs are produced in order to meet ONS’ role to produce statistics for the public good. Should outputs contain any data, this data will be aggregated with small numbers supressed.

Any official statistics produced will be published so that they are publicly available - for example on the ONS website, in statistical bulletins, analysis articles or on data dashboards.

Projects focused on new topics or new data sources will include exploration of the feasibility of using and/or linking the data. They will also quality assess the data and linkage prior to full development of analyses and publication of statistics. Briefings for technical/expert audiences or methodology reports may be written for internal use in the development and assessment of new data sources and analysis. These reports will be published alongside experimental statistics or official statistics on the ONS website or in peer-reviewed journals as appropriate.

All ONS statistical teams engage regularly with users and will seek to provide frequent updates on the production of official statistics through regular stakeholder conversations, presentations and events.

ONS have a publishing strategy and team which supports analytical teams in developing different outputs to suit a range of different audiences. ONS also has active communications, media and social media teams to promote dissemination of statistics and enable outputs to reach a wide-ranging audience.

Census and Data Collection Transformation Programme (CDCTP)

ONS has committed to publishing regular annual Administrative Data Research Outputs (ABPEs) on the population, including estimates on the size of the population (produced using administrative data).

The aims of these research outputs are to:

- Update users on the progress made through administrative data and to seek feedback from users - the aim being to improve the methods used.

- Aid the process of working with data suppliers to improve data quality for statistical purposes.

ONS has already developed ABPEs in both method and content in the run up to the 2021 Census and plan to compare the ABPEs with results from the 2021 Census. ONS will also expand on the range of topics and granularity of information published each year.

ONS recognise the need for continued development of their methodology. Future releases will therefore include further outputs based on future methodology developments which hope to allow for user feedback, newly available data and alternative techniques to facilitate the production of population statistics.

The research on the feasibility of producing administrative, data-based characteristics estimates that ONS should be able to provide evidence to feed into the 2023 recommendation on the future of the Census. ONS aim to produce research outputs on the progress they have made on the feasibility research they’re conducting on user feedback. The outputs will be in the form of aggregate statistics, with statistics disclosure rules applied where necessary.

Population and Migration

Main publication dates are as follows:

Internal migration - Annually – June

Internal migration statistics are published at local authority level by age and sex. They are used widely by local authorities and academics to, for example, feed into alternative population projections models and subsequent resource allocation planning.

Mid-year estimates - Annually - June, with lower-level geography releases after this until Small Area Population Estimates are released in November.

National Population projections - normally published at the end of October. Releases have traditionally been produced bi-annually. Following the release of the national projections, there are now sub-national releases between national releases.

Internal migration estimates form a key component of population estimates and population projections, which are of important use in the UK. Estimates are used by central government, local government and health authorities to support resource allocation as well as forming a fundamental basis for other statistics across government which feed into policy decisions.

Projections are used to determine the future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services needed - for example a hospital may use projections to determine whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Health and Mortality Analysis

Specific outputs will include published aggregate statistics on the number, characteristics and condition of population groups such as the social care, care home and disabled population (providing more detail on specific impairments). ONS will produce mortality, morbidity and life expectancy statistics by protected characteristics such as ethnicity, disability and specific age groups.

PDS data has been integral for:

• Research in developing an approach for producing Admin Based Population Estimates (ABPEs), formerly known as SPDs. By combining PDS with income, education and life event data sources and applying an activity based approach, ONS have published two ABPE time series for 2016-2020 (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/developingadminbasedpopulationestimatesenglandandwales/2016to2020). Analysing these time series helps ONS understand if and how the quality of the estimates change over time, which feeds into ONS' future methodological improvements.

• Understanding any changes in the way the population interacts with health registration systems and whether there have been changes to these patterns during the pandemic. This information will support ONS in further developing their ABPEs.

• Providing address information for the population and helping ONS understand changes in population between local areas and over time.

Census Statistical Outputs Design are using the PDS data to quality assure the Census. In preparation for the census ONS used PDS data to understand the quality of the address frame planned for use. The frame is the list of addresses ONS use as the basis for making initial contact with the public. ONS analysts looked for evidence of where there was a clustering of addresses which were on the PDS but not on the frame, for example a newly built block of flats.

As part of quality assurance of the census statistics ONS have a systematic approach to validating against a range of data and other statistics. This includes the PDS. Where inconsistencies are seen between the census and the PDS, analysts take a deeper look at ONS statistics to understand whether there is evidence of an issue with the census process. As an example this could include if ONS data has missed a student hall of residence.

In compiling the final census estimates ONS has also used the PDS to understand whether there is any systematic bias in how the size of the population has been estimated. ONS’ final statistics are estimates as they aren’t simply the number of people of people who completed a questionnaire, instead analysts adjust for the number of people who were not included on a form. ONS used PDS data to validate the assumptions made in this modelling.

The Centre for International Migration have previously linked the PDS to HMRC's Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many 'new migrants' on the MWS are seen in PDS. This is part of ONS' wider work to link different administrative data sources together and to test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

Using PR (in future PDS) data ONS have linked census and deaths data to produce new insights on the ethnic differences in mortality and life expectancy.

The Data Recipient agrees to process the Data only for the following purposes, as agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act (SRSA) 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board carries out this function. Within ONS, the Health, Population and Methods Group are responsible for providing key data on the population of the United Kingdom and are comprised of a number of divisions that undertake demographic analysis in, for example, migration, fertility, mortality, life expectancy, ageing and families. These analyses are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to, from time to time, collect and publish any statistical information relating to the number and condition of the population in the interval between one census and another and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the SRSA 2007.

ONS rely on the following lawful bases under the General Data Protection Regulation for processing personal data including special categories of personal data:

• GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

• GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom's National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business and enable better decisions to be made. Using administrative data such as Personal Demographics Service (PDS) allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census and population statistics – more detailed justifications are outlined in greater depth below. Proportionality is considered by business areas who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address, and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out under this Agreement will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by employees of ONS or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions, thus ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading 'Data Environment'.

Population Statistics

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. PDS stocks are also to be used in place of the now defunct PR data to produce small area population estimates at Lower Layer Super Output Area (LSOA), Middle Layer Super Output Area (MSOA), Output Area (OA), ward, Clinical Commissioning Group (CCG), parliamentary constituencies, and National Park levels. With the loss of the NHAIS posting information, the PDS will be used to produce estimates of internal migration - therefore more detailed address information is required from weekly PDS updates so that the address data can be run through ONS’ Address Index Matching System (AIMS). The PDS will also help ONS to understand how migrants interact with services.

Internal migration estimates are national statistics and are a key component in population estimates, projections and national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, for estimating the local authority distribution of international migrants component of change mid-year estimates and small area population estimates within England and Wales and for estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students and data from HMRC and DWP.

Census and Data Collection Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

• Population and housing estimates: counts of the population by age and sex, and the number of housing units.

• Population structures: households, families and household relationships.

• Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. The Census also provides a precise estimate of the UK population. Any statistics produced that relate to the general population are understood by comparing against this estimate. Mortality rates, household income, disease prevalence, employment rates, vaccination rates and more all rely on an accurate population estimate. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended to the Board of the UK Statistics Authority that the future provision of population statistics and the next census should be through:

"An online census of all households and communal establishments in England and Wales in 2021 recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses."

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

'Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA's plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.' - Government's response to the National Statistician's recommendation, 18 July 2014.

The Census and Data Collection Transformation Programme (CDCTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether, in ONS' view, the Government's ambition can be realised. To that end, ONS has committed to publishing an annual assessment of progress towards the Government's ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. Since 2015 ONS has produced annual Admin Based Population Estimates (ABPEs), formerly known as Statistical Population Datasets (SPDs), based on linking multiple administrative datasets (including NHS Patient Registration (PR) Data, Department for Work and Pensions (DWP)/Her Majesty’s Revenue and Customs (HMRC), Customer Information System data and higher education data).

No one dataset in its' own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics by helping to address issues relating to definitional differences between administrative data and population definitions and time lags.

There is no common identifier that can be used to link individuals' records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, full name, addresses and postcodes) to link the datasets and establish the aforementioned ABPEs. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data was needed to support the 2021 Census and continues to be needed to provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021, whilst also ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other administrative data sources, however no clinical data is being requested. Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce ABPEs and allow analyses to meet the 2023 recommendation of the future of the Census.

Census 2021 Quality Assurance

ONS conducted the Census for England and Wales on 21st March 2021, which is one of the most important and highest profile National Statistical productions. The Census will provide a decennial picture of the size and state of the population and will feed directly into funding and service provision policies. Although the Census is mandatory, not everyone is captured. Data collected in the Census can be compared with data from the PDS to ensure it is reliable and will allow ONS to gather data needed to inform work around the Census. This will help ONS to quality assure Census returns and prepare outputs.

International Migration

The Centre for International Migration is leading on work to transform international migration statistics through the development of administrative data-based migration estimates (ABMEs) that will better meet user needs for timely and accurate statistics on this topic area. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee's report and government response.

The PDS data forms an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved international migration estimates at local level. Improved statistics, at a more granular level, may enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data hopes to allow the centre to:

• Compare signs of the arrival, activity and departures of international migrants by linking PDS to other public sector datasets.

• Use knowledge and information from PDS to inform ABMEs and modelled estimates of international migration.

• Provide analysis and research into how international migrants interact with the health system and the impact of international migration on the health sector, including via linkage to other public sector datasets.

ONS use PR/PDS data to carry out population level analysis. PDS data includes address and date of birth variables which can be used as analytical variables for population groups for example. This may facilitate the creation of location-based variables or flags for analysis. By using the PDS data to assign 'location-based variables' ONS can ensure population indicators collected in other linked data sources such as the Census are updated to reflect the most recent living situation of the population of interest. For example, between the 10-yearly census information on the size and condition of the population living in deprived areas, information on small geographic locations or communal establishments (such as care homes) are not readily available. PDS data can be used to identify and quantify the size of these populations. The PDS data can also be used alongside other data sources such as Provider Information Returns data held by the Care Quality Commission to identify and better understand the characteristics of the population receiving social care.

To note, ONS analysts do not actually scrutinize individual rows of data, rather they run models on large scale datasets with millions of rows, and then scrutinize the outputs and aggregate results. Once aggregated ONS analysts will never try to identify or re-identify individuals.

The outputs expected from this work include statistics, statistical reports, presentations, methodology papers and analyses. All outputs are produced in order to meet ONS’ role to produce statistics for the public good. Should outputs contain any data, this data will be aggregated with small numbers supressed.

Any official statistics produced will be published so that they are publicly available - for example on the ONS website, in statistical bulletins, analysis articles or on data dashboards.

Projects focused on new topics or new data sources will include exploration of the feasibility of using and/or linking the data. They will also quality assess the data and linkage prior to full development of analyses and publication of statistics. Briefings for technical/expert audiences or methodology reports may be written for internal use in the development and assessment of new data sources and analysis. These reports will be published alongside experimental statistics or official statistics on the ONS website or in peer-reviewed journals as appropriate.

All ONS statistical teams engage regularly with users and will seek to provide frequent updates on the production of official statistics through regular stakeholder conversations, presentations and events.

ONS have a publishing strategy and team which supports analytical teams in developing different outputs to suit a range of different audiences. ONS also has active communications, media and social media teams to promote dissemination of statistics and enable outputs to reach a wide-ranging audience.

Census and Data Collection Transformation Programme (CDCTP)

ONS has committed to publishing regular annual Administrative Data Research Outputs (ABPEs) on the population, including estimates on the size of the population (produced using administrative data).

The aims of these research outputs are to:

- Update users on the progress made through administrative data and to seek feedback from users - the aim being to improve the methods used.

- Aid the process of working with data suppliers to improve data quality for statistical purposes.

ONS has already developed ABPEs in both method and content in the run up to the 2021 Census and plan to compare the ABPEs with results from the 2021 Census. ONS will also expand on the range of topics and granularity of information published each year.

ONS recognise the need for continued development of their methodology. Future releases will therefore include further outputs based on future methodology developments which hope to allow for user feedback, newly available data and alternative techniques to facilitate the production of population statistics.

The research on the feasibility of producing administrative, data-based characteristics estimates that ONS should be able to provide evidence to feed into the 2023 recommendation on the future of the Census. ONS aim to produce research outputs on the progress they have made on the feasibility research they’re conducting on user feedback. The outputs will be in the form of aggregate statistics, with statistics disclosure rules applied where necessary.

Population and Migration

Main publication dates are as follows:

Internal migration - Annually – June

Internal migration statistics are published at local authority level by age and sex. They are used widely by local authorities and academics to, for example, feed into alternative population projections models and subsequent resource allocation planning.

Mid-year estimates - Annually - June, with lower-level geography releases after this until Small Area Population Estimates are released in November.

National Population projections - normally published at the end of October. Releases have traditionally been produced bi-annually. Following the release of the national projections, there are now sub-national releases between national releases.

Internal migration estimates form a key component of population estimates and population projections, which are of important use in the UK. Estimates are used by central government, local government and health authorities to support resource allocation as well as forming a fundamental basis for other statistics across government which feed into policy decisions.

Projections are used to determine the future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services needed - for example a hospital may use projections to determine whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Health and Mortality Analysis

Specific outputs will include published aggregate statistics on the number, characteristics and condition of population groups such as the social care, care home and disabled population (providing more detail on specific impairments). ONS will produce mortality, morbidity and life expectancy statistics by protected characteristics such as ethnicity, disability and specific age groups.

PDS data has been integral for:

• Research in developing an approach for producing Admin Based Population Estimates (ABPEs), formerly known as SPDs. By combining PDS with income, education and life event data sources and applying an activity based approach, ONS have published two ABPE time series for 2016-2020 (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/developingadminbasedpopulationestimatesenglandandwales/2016to2020). Analysing these time series helps ONS understand if and how the quality of the estimates change over time, which feeds into ONS' future methodological improvements.

• Understanding any changes in the way the population interacts with health registration systems and whether there have been changes to these patterns during the pandemic. This information will support ONS in further developing their ABPEs.

• Providing address information for the population and helping ONS understand changes in population between local areas and over time.

Census Statistical Outputs Design are using the PDS data to quality assure the Census. In preparation for the census ONS used PDS data to understand the quality of the address frame planned for use. The frame is the list of addresses ONS use as the basis for making initial contact with the public. ONS analysts looked for evidence of where there was a clustering of addresses which were on the PDS but not on the frame, for example a newly built block of flats.

As part of quality assurance of the census statistics ONS have a systematic approach to validating against a range of data and other statistics. This includes the PDS. Where inconsistencies are seen between the census and the PDS, analysts take a deeper look at ONS statistics to understand whether there is evidence of an issue with the census process. As an example this could include if ONS data has missed a student hall of residence.

In compiling the final census estimates ONS has also used the PDS to understand whether there is any systematic bias in how the size of the population has been estimated. ONS’ final statistics are estimates as they aren’t simply the number of people of people who completed a questionnaire, instead analysts adjust for the number of people who were not included on a form. ONS used PDS data to validate the assumptions made in this modelling.

The Centre for International Migration have previously linked the PDS to HMRC's Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many 'new migrants' on the MWS are seen in PDS. This is part of ONS' wider work to link different administrative data sources together and to test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

Using PR (in future PDS) data ONS have linked census and deaths data to produce new insights on the ethnic differences in mortality and life expectancy.

The Data Recipient agrees to process the Data only for the following purposes, as agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act (SRSA) 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board carries out this function. Within ONS, the Health, Population and Methods Group are responsible for providing key data on the population of the United Kingdom and are comprised of a number of divisions that undertake demographic analysis in, for example, migration, fertility, mortality, life expectancy, ageing and families. These analyses are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to, from time to time, collect and publish any statistical information relating to the number and condition of the population in the interval between one census and another and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the SRSA 2007.

ONS rely on the following lawful bases under the General Data Protection Regulation for processing personal data including special categories of personal data:

• GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

• GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom's National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business and enable better decisions to be made. Using administrative data such as Personal Demographics Service (PDS) allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census and population statistics – more detailed justifications are outlined in greater depth below. Proportionality is considered by business areas who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address, and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out under this Agreement will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by employees of ONS or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions, thus ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading 'Data Environment'.

Population Statistics

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. PDS stocks are also to be used in place of the now defunct PR data to produce small area population estimates at Lower Layer Super Output Area (LSOA), Middle Layer Super Output Area (MSOA), Output Area (OA), ward, Clinical Commissioning Group (CCG), parliamentary constituencies, and National Park levels. With the loss of the NHAIS posting information, the PDS will be used to produce estimates of internal migration - therefore more detailed address information is required from weekly PDS updates so that the address data can be run through ONS’ Address Index Matching System (AIMS). The PDS will also help ONS to understand how migrants interact with services.

Internal migration estimates are national statistics and are a key component in population estimates, projections and national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, for estimating the local authority distribution of international migrants component of change mid-year estimates and small area population estimates within England and Wales and for estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students and data from HMRC and DWP.

Census and Data Collection Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

• Population and housing estimates: counts of the population by age and sex, and the number of housing units.

• Population structures: households, families and household relationships.

• Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. The Census also provides a precise estimate of the UK population. Any statistics produced that relate to the general population are understood by comparing against this estimate. Mortality rates, household income, disease prevalence, employment rates, vaccination rates and more all rely on an accurate population estimate. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended to the Board of the UK Statistics Authority that the future provision of population statistics and the next census should be through:

"An online census of all households and communal establishments in England and Wales in 2021 recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses."

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

'Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA's plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.' - Government's response to the National Statistician's recommendation, 18 July 2014.

The Census and Data Collection Transformation Programme (CDCTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether, in ONS' view, the Government's ambition can be realised. To that end, ONS has committed to publishing an annual assessment of progress towards the Government's ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. Since 2015 ONS has produced annual Admin Based Population Estimates (ABPEs), formerly known as Statistical Population Datasets (SPDs), based on linking multiple administrative datasets (including NHS Patient Registration (PR) Data, Department for Work and Pensions (DWP)/Her Majesty’s Revenue and Customs (HMRC), Customer Information System data and higher education data).

No one dataset in its' own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics by helping to address issues relating to definitional differences between administrative data and population definitions and time lags.

There is no common identifier that can be used to link individuals' records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, full name, addresses and postcodes) to link the datasets and establish the aforementioned ABPEs. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data was needed to support the 2021 Census and continues to be needed to provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021, whilst also ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other administrative data sources, however no clinical data is being requested. Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce ABPEs and allow analyses to meet the 2023 recommendation of the future of the Census.

Census 2021 Quality Assurance

ONS conducted the Census for England and Wales on 21st March 2021, which is one of the most important and highest profile National Statistical productions. The Census will provide a decennial picture of the size and state of the population and will feed directly into funding and service provision policies. Although the Census is mandatory, not everyone is captured. Data collected in the Census can be compared with data from the PDS to ensure it is reliable and will allow ONS to gather data needed to inform work around the Census. This will help ONS to quality assure Census returns and prepare outputs.

International Migration

The Centre for International Migration is leading on work to transform international migration statistics through the development of administrative data-based migration estimates (ABMEs) that will better meet user needs for timely and accurate statistics on this topic area. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee's report and government response.

The PDS data forms an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved international migration estimates at local level. Improved statistics, at a more granular level, may enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data hopes to allow the centre to:

• Compare signs of the arrival, activity and departures of international migrants by linking PDS to other public sector datasets.

• Use knowledge and information from PDS to inform ABMEs and modelled estimates of international migration.

• Provide analysis and research into how international migrants interact with the health system and the impact of international migration on the health sector, including via linkage to other public sector datasets.

ONS use PR/PDS data to carry out population level analysis. PDS data includes address and date of birth variables which can be used as analytical variables for population groups for example. This may facilitate the creation of location-based variables or flags for analysis. By using the PDS data to assign 'location-based variables' ONS can ensure population indicators collected in other linked data sources such as the Census are updated to reflect the most recent living situation of the population of interest. For example, between the 10-yearly census information on the size and condition of the population living in deprived areas, information on small geographic locations or communal establishments (such as care homes) are not readily available. PDS data can be used to identify and quantify the size of these populations. The PDS data can also be used alongside other data sources such as Provider Information Returns data held by the Care Quality Commission to identify and better understand the characteristics of the population receiving social care.

To note, ONS analysts do not actually scrutinize individual rows of data, rather they run models on large scale datasets with millions of rows, and then scrutinize the outputs and aggregate results. Once aggregated ONS analysts will never try to identify or re-identify individuals.

The outputs expected from this work include statistics, statistical reports, presentations, methodology papers and analyses. All outputs are produced in order to meet ONS’ role to produce statistics for the public good. Should outputs contain any data, this data will be aggregated with small numbers supressed.

Any official statistics produced will be published so that they are publicly available - for example on the ONS website, in statistical bulletins, analysis articles or on data dashboards.

Projects focused on new topics or new data sources will include exploration of the feasibility of using and/or linking the data. They will also quality assess the data and linkage prior to full development of analyses and publication of statistics. Briefings for technical/expert audiences or methodology reports may be written for internal use in the development and assessment of new data sources and analysis. These reports will be published alongside experimental statistics or official statistics on the ONS website or in peer-reviewed journals as appropriate.

All ONS statistical teams engage regularly with users and will seek to provide frequent updates on the production of official statistics through regular stakeholder conversations, presentations and events.

ONS have a publishing strategy and team which supports analytical teams in developing different outputs to suit a range of different audiences. ONS also has active communications, media and social media teams to promote dissemination of statistics and enable outputs to reach a wide-ranging audience.

Census and Data Collection Transformation Programme (CDCTP)

ONS has committed to publishing regular annual Administrative Data Research Outputs (ABPEs) on the population, including estimates on the size of the population (produced using administrative data).

The aims of these research outputs are to:

- Update users on the progress made through administrative data and to seek feedback from users - the aim being to improve the methods used.

- Aid the process of working with data suppliers to improve data quality for statistical purposes.

ONS has already developed ABPEs in both method and content in the run up to the 2021 Census and plan to compare the ABPEs with results from the 2021 Census. ONS will also expand on the range of topics and granularity of information published each year.

ONS recognise the need for continued development of their methodology. Future releases will therefore include further outputs based on future methodology developments which hope to allow for user feedback, newly available data and alternative techniques to facilitate the production of population statistics.

The research on the feasibility of producing administrative, data-based characteristics estimates that ONS should be able to provide evidence to feed into the 2023 recommendation on the future of the Census. ONS aim to produce research outputs on the progress they have made on the feasibility research they’re conducting on user feedback. The outputs will be in the form of aggregate statistics, with statistics disclosure rules applied where necessary.

Population and Migration

Main publication dates are as follows:

Internal migration - Annually – June

Internal migration statistics are published at local authority level by age and sex. They are used widely by local authorities and academics to, for example, feed into alternative population projections models and subsequent resource allocation planning.

Mid-year estimates - Annually - June, with lower-level geography releases after this until Small Area Population Estimates are released in November.

National Population projections - normally published at the end of October. Releases have traditionally been produced bi-annually. Following the release of the national projections, there are now sub-national releases between national releases.

Internal migration estimates form a key component of population estimates and population projections, which are of important use in the UK. Estimates are used by central government, local government and health authorities to support resource allocation as well as forming a fundamental basis for other statistics across government which feed into policy decisions.

Projections are used to determine the future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services needed - for example a hospital may use projections to determine whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Health and Mortality Analysis

Specific outputs will include published aggregate statistics on the number, characteristics and condition of population groups such as the social care, care home and disabled population (providing more detail on specific impairments). ONS will produce mortality, morbidity and life expectancy statistics by protected characteristics such as ethnicity, disability and specific age groups.

PDS data has been integral for:

• Research in developing an approach for producing Admin Based Population Estimates (ABPEs), formerly known as SPDs. By combining PDS with income, education and life event data sources and applying an activity based approach, ONS have published two ABPE time series for 2016-2020 (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/developingadminbasedpopulationestimatesenglandandwales/2016to2020). Analysing these time series helps ONS understand if and how the quality of the estimates change over time, which feeds into ONS' future methodological improvements.

• Understanding any changes in the way the population interacts with health registration systems and whether there have been changes to these patterns during the pandemic. This information will support ONS in further developing their ABPEs.

• Providing address information for the population and helping ONS understand changes in population between local areas and over time.

Census Statistical Outputs Design are using the PDS data to quality assure the Census. In preparation for the census ONS used PDS data to understand the quality of the address frame planned for use. The frame is the list of addresses ONS use as the basis for making initial contact with the public. ONS analysts looked for evidence of where there was a clustering of addresses which were on the PDS but not on the frame, for example a newly built block of flats.

As part of quality assurance of the census statistics ONS have a systematic approach to validating against a range of data and other statistics. This includes the PDS. Where inconsistencies are seen between the census and the PDS, analysts take a deeper look at ONS statistics to understand whether there is evidence of an issue with the census process. As an example this could include if ONS data has missed a student hall of residence.

In compiling the final census estimates ONS has also used the PDS to understand whether there is any systematic bias in how the size of the population has been estimated. ONS’ final statistics are estimates as they aren’t simply the number of people of people who completed a questionnaire, instead analysts adjust for the number of people who were not included on a form. ONS used PDS data to validate the assumptions made in this modelling.

The Centre for International Migration have previously linked the PDS to HMRC's Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many 'new migrants' on the MWS are seen in PDS. This is part of ONS' wider work to link different administrative data sources together and to test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

Using PR (in future PDS) data ONS have linked census and deaths data to produce new insights on the ethnic differences in mortality and life expectancy.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital. No new data will be disseminated under this Agreement:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority- UKSA) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board ( carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e)The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timelier at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (National Health Application and Infrastructure Service- NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance, higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual’s interactions with this system. Th‘s 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government’s ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government’s ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those that do not present on both datasets. If ONS cannot understand the root causes of the differences, then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for the analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Since the last Data Access Request Service was agreed ONS have continued to work with the PDS data to understand the size and structure of the population, the characteristics of the population, and how the population change over time.

PDS has been integral for:

• Research in developing an approach for producing Admin Based Population Estimates (ABPEs), formerly known as SPDs. By combining PDS with income, education and life event data sources and applying an activity based approach, we have published two ABPE time series for 2016-2020 (https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/developingadminbasedpopulationestimatesenglandandwales/2016to2020). Analysing these time series helps us understand if and how the quality of the estimates change over time which feeds into our future methodological improvements.

• Understanding any changes in the way the population interact with health registration systems and whether there have been changes to these patterns during the pandemic. This information will inform our research to further develop our ABPEs.

• Providing address information for the population and helping us to understand changes in population, between local areas and over time.

Census Statistical Outputs Design are using the PDS to aid in the quality assurance of Census. In preparation for the census ONS used PDS data to understand the quality of the address frame planned for use. The frame is the list of addresses ONS use as the basis for making initial contact with the public. ONS analysts looked for evidence of where there was clustering of addresses which were on the PDS which were not on our frame, for example a newly built block of flats.

As part of quality assurance of the census statistics ONS have a systematic approach to validating against a range of data and other statistics. This includes the PDS. Where inconsistencies are seen between the census and the PDS, analysts take a deeper look at ONS statistics to understand whether there is evidence of an issue with the census process. As an example this could include if ONS data has missed a student hall of residence.

In compiling the final census estimates ONS has also used the PDS to understand whether there is any systematic bias in how the size of the population has been estimated. ONS’s final statistics are estimates as they aren’t simply the number of people of people who completed a questionnaire, instead analysts adjust for the number of people who were not included on a form. ONS used PDS data to validate the assumptions made in this modelling.

The Centre for International Migration have previously linked the PDS to HMRC's Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many 'new migrants' on the MWS are seen in PDS. This is part of ONS' wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

Using PR (in future PDS) data ONS have linked census and deaths data to produce new insights on the ethnic differences in mortality and life expectancy.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital. No new data will be disseminated under this Agreement:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority- UKSA) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board ( carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e)The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timelier at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (National Health Application and Infrastructure Service- NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance, higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual’s interactions with this system. Th‘s 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government’s ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government’s ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those that do not present on both datasets. If ONS cannot understand the root causes of the differences, then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for the analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Statistical Design and Research

The following developments have been made:

• ONS have conducted quality assurance analysis on the dataset, which has fed into internal report on the dataset.

• ONS have received Name variables from NHS Digital as part of the extract received which now feeds into analysis.

• PDS has been used as a tool to quality assure the linkage of address data between PR and CIS in a previous SPD publication.

• PDS has been used as for the quality assurance of Births and Deaths Registration data which will feed into the migration publication to be released by ONS in late autumn 2018.

• PDS has primarily been used to link to other datasets and develop an iterative methodology to produce population and migration estimates. Early parts of this work were presented at the British Society of Population Studies (BSPS) conference earlier this year.

Going forward, within SDR one of the key uses of PDS will be continuing to link the data to a range of other datasets at record level to develop a methodology to produce population and migration estimates by sex and age to levels of geography currently published by the official Population Estimates going forward.

ONS have recently raised a request for a number of additional variables to be delivered going forward however discussions surrounding the acquisition of these variables is ongoing so no further update can be provided on specific variables. The key variables that have been requested are those which provide some form of identification which is descriptive of a person and any variable which would highlight activity.

Additionally, it is likely be used to pick up the demographic information that is missing on other datasets, for example HES and IAPT, to allow for easier, more consistent linkage.

Census Statistical Outputs Design

Census Statistical Outputs Design are hoping to use the PDS to aid in the imputation and quality assurance of Census, particularly of people resident in communal establishments such as care homes and mental health establishments. This mirrors what was done in 2011 using the PR. Response to Census in communal establishments is variable, and it’s not always clear where non-respondents are located due to unreliable administrative data estimates about the care homes themselves (referring to total capacity rather than occupied capacity). It is hoped that if a person is usually resident in a care home, the chances of them not appearing on the PDS will be small. Therefore, estimates of currently occupied beds in care homes derived from the PDS linked to a list of identified care homes and then compared to Census responses for that care home will identify approximate numbers of people missing from that care home’s Census responses. Demographic information from the PDS for that care home can then be used to determine appropriate types of donor records to impute missing responses. Work to develop this approach is ongoing, with a test of the approach to be conducted during the 2019 Rehearsal.

Migration Statistics Division

The Centre for International Migration have linked the PDS to HMRC’s Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many ‘new migrants’ on the MWS are seen in PDS. This is part of ONS’ wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital. No new data will be disseminated under this Agreement:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority- UKSA) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics (ONS) as the Executive Office of The Board ( carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e)The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timelier at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigorous disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (National Health Application and Infrastructure Service- NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance, higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual’s interactions with this system. Th‘s 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government’s ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government’s ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those that do not present on both datasets. If ONS cannot understand the root causes of the differences, then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for the analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Statistical Design and Research

Since the last Data Access Request Service was agreed, the following developments have been made:

• ONS have conducted quality assurance analysis on the dataset, which has fed into internal report on the dataset.

• ONS have received Name variables from NHS Digital as part of the extract received which now feeds into analysis.

• PDS has been used as a tool to quality assure the linkage of address data between PR and CIS in a previous SPD publication.

• PDS has been used as for the quality assurance of Births and Deaths Registration data which will feed into the migration publication to be released by ONS in late autumn 2018.

• PDS has primarily been used to link to other datasets and develop an iterative methodology to produce population and migration estimates. Early parts of this work were presented at the British Society of Population Studies (BSPS) conference earlier this year.

Going forward, within SDR one of the key uses of PDS will be continuing to link the data to a range of other datasets at record level to develop a methodology to produce population and migration estimates by sex and age to levels of geography currently published by the official Population Estimates going forward.

ONS have recently raised a request for a number of additional variables to be delivered going forward however discussions surrounding the acquisition of these variables is ongoing so no further update can be provided on specific variables. The key variables that have been requested are those which provide some form of identification which is descriptive of a person and any variable which would highlight activity.

Additionally, it is likely be used to pick up the demographic information that is missing on other datasets, for example HES and IAPT, to allow for easier, more consistent linkage.

Census Statistical Outputs Design

Census Statistical Outputs Design are hoping to use the PDS to aid in the imputation and quality assurance of Census, particularly of people resident in communal establishments such as care homes and mental health establishments. This mirrors what was done in 2011 using the PR. Response to Census in communal establishments is variable, and it’s not always clear where non-respondents are located due to unreliable administrative data estimates about the care homes themselves (referring to total capacity rather than occupied capacity). It is hoped that if a person is usually resident in a care home, the chances of them not appearing on the PDS will be small. Therefore, estimates of currently occupied beds in care homes derived from the PDS linked to a list of identified care homes and then compared to Census responses for that care home will identify approximate numbers of people missing from that care home’s Census responses. Demographic information from the PDS for that care home can then be used to determine appropriate types of donor records to impute missing responses. Work to develop this approach is ongoing, with a test of the approach to be conducted during the 2019 Rehearsal.

Migration Statistics Division

The Centre for International Migration have linked the PDS to HMRC’s Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many ‘new migrants’ on the MWS are seen in PDS. This is part of ONS’ wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics as the Executive Office of The Board (ONS) carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

ONS does not consider there to be any moral or ethical issues raised by the proposed dissemination. An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigours disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government's ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually-resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those not present on both datasets. If ONS cannot understand the root causes of the differences then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for the analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Statistical Design and Research

Since the last Data Access Request Service was agreed, the following developments have been made:

• ONS have conducted quality assurance analysis on the dataset, which has fed into internal report on the dataset.

• ONS have received Name variables from NHS-Digital as part of the extract received which now feeds into analysis.

• PDS has been used as a tool to quality assure the linkage of address data between PR and CIS in a previous SPD publication.

• PDS has been used as for the quality assurance of Births and Deaths Registration data which will feed into the migration publication to be released by ONS in late autumn 2018.

• PDS has primarily been used to link to other datasets and develop an iterative methodology to produce population and migration estimates. Early parts of this work were presented at the British Society of Population Studies (BSPS) conference earlier this year.

Going forward, within SDR one of the key uses of PDS will be continuing to link the data to a range of other datasets at record level to develop a methodology to produce population and migration estimates by sex and age to levels of geography currently published by the official Population Estimates going forward.

ONS have recently raised a request for a number of additional variables to be delivered going forward however discussions surrounding the acquisition of these variables is ongoing so no further update can be provided on specific variables. The key variables that have been requested are those which provide some form of identification which is descriptive of a person and any variable which would highlight activity.

Additionally, it is likely be used to pick up the demographic information that is missing on other datasets, for example HES and IAPT, to allow for easier, more consistent linkage.

Census Statistical Outputs Design

Census Statistical Outputs Design are hoping to use the PDS to aid in the imputation and quality assurance of Census, particularly of people resident in communal establishments such as care homes and mental health establishments. This mirrors what was done in 2011 using the PR. Response to Census in communal establishments is variable, and it’s not always clear where non-respondents are located due to unreliable administrative data estimates about the care homes themselves (referring to total capacity rather than occupied capacity). It is hoped that if a person is usually resident in a care home, the chances of them not appearing on the PDS will be small. Therefore, estimates of currently occupied beds in care homes derived from the PDS linked to a list of identified care homes and then compared to Census responses for that care home will identify approximate numbers of people missing from that care home’s Census responses. Demographic information from the PDS for that care home can then be used to determine appropriate types of donor records to impute missing responses. Work to develop this approach is ongoing, with a test of the approach to be conducted during the 2019 Rehearsal.

Migration Statistics Division

The Centre for International Migration have linked the PDS to HMRC’s Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many ‘new migrants’ on the MWS are seen in PDS. This is part of ONS’ wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics as the Executive Office of The Board (ONS) carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

ONS does not consider there to be any moral or ethical issues raised by the proposed dissemination. An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigours disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government's ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually-resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those not present on both datasets. If ONS cannot understand the root causes of the differences then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for the analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Statistical Design and Research

Since the last Data Access Request Service was agreed, the following developments have been made:

• ONS have conducted quality assurance analysis on the dataset, which has fed into internal report on the dataset.

• ONS have received Name variables from NHS-Digital as part of the extract received which now feeds into analysis.

• PDS has been used as a tool to quality assure the linkage of address data between PR and CIS in a previous SPD publication.

• PDS has been used as for the quality assurance of Births and Deaths Registration data which will feed into the migration publication to be released by ONS in late autumn 2018.

• PDS has primarily been used to link to other datasets and develop an iterative methodology to produce population and migration estimates. Early parts of this work were presented at the British Society of Population Studies (BSPS) conference earlier this year.

Going forward, within SDR one of the key uses of PDS will be continuing to link the data to a range of other datasets at record level to develop a methodology to produce population and migration estimates by sex and age to levels of geography currently published by the official Population Estimates going forward.

ONS have recently raised a request for a number of additional variables to be delivered going forward however discussions surrounding the acquisition of these variables is ongoing so no further update can be provided on specific variables. The key variables that have been requested are those which provide some form of identification which is descriptive of a person and any variable which would highlight activity.

Additionally, it is likely be used to pick up the demographic information that is missing on other datasets, for example HES and IAPT, to allow for easier, more consistent linkage.

Census Statistical Outputs Design

Census Statistical Outputs Design are hoping to use the PDS to aid in the imputation and quality assurance of Census, particularly of people resident in communal establishments such as care homes and mental health establishments. This mirrors what was done in 2011 using the PR. Response to Census in communal establishments is variable, and it’s not always clear where non-respondents are located due to unreliable administrative data estimates about the care homes themselves (referring to total capacity rather than occupied capacity). It is hoped that if a person is usually resident in a care home, the chances of them not appearing on the PDS will be small. Therefore, estimates of currently occupied beds in care homes derived from the PDS linked to a list of identified care homes and then compared to Census responses for that care home will identify approximate numbers of people missing from that care home’s Census responses. Demographic information from the PDS for that care home can then be used to determine appropriate types of donor records to impute missing responses. Work to develop this approach is ongoing, with a test of the approach to be conducted during the 2019 Rehearsal.

Migration Statistics Division

The Centre for International Migration have linked the PDS to HMRC’s Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many ‘new migrants’ on the MWS are seen in PDS. This is part of ONS’ wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.

The Data Recipient agrees to process the Data only for the following purposes agreed with NHS Digital:

Statutory purpose

Under section 20 of the Statistics and Registration Service Act 2007 the Statistics Board (UK Statistics Authority) may itself produce and publish statistics on any matter relating to the UK or any part of it. The Office for National Statistics as the Executive Office of The Board (ONS) carries out this function. Within ONS, Population Statistics Division are responsible for providing key data on the population of the United Kingdom and are comprised of several branches that undertake demographic analysis in migration, fertility, mortality, ageing and families which are used to create population estimates, population projections, the Migration Statistics Quarterly Report and other demographic analytical outputs.

Under section 5 of the Census Act 1920 the Registrar-General has a duty to from time to time collect and publish any statistical information with respect to the number and condition of the population in the interval between one census and another…and the Registrar-General may make arrangements with any Government Department for the purpose of acquiring any materials or information necessary for the purpose aforesaid. This duty was transferred from the Registrar-General to the Statistics Board under s.25(2)(a) of the 2007 Act.

ONS will rely on the following lawful basis from the GDPR for processing personal data including special category personal data:

GDPR Article 6(1)(e) The processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the data controller. The authority for ONS to produce, promote and safeguard official statistics is found in the Statistics and Registration Service Act 2007.

GDPR Article 9(2)(j) Processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes in accordance with Article 89(1) based on Union or Member State law which shall be proportionate to the aim pursued, respect the essence of the right to data protection and provide for suitable and specific measures to safeguard the fundamental rights and the interests of the data subject.

ONS is the United Kingdom’s National Statistical Institute and largest independent producer of official statistics. It is responsible for producing statistics on a range of key economic, social and demographic topics in order to inform the needs of Government, society, academia and business to enable better decisions to be made. Using administrative data such as PDS allows ONS to produce statistics which are more granular and timely at a lower cost to the public, therefore enabling better decisions and resource allocation.

The specific necessity of processing these data is to develop census statistics and population and migration estimates: these justifications are outlined in greater depth below. Proportionality is considered by business areas, who are required to demonstrate that their goals cannot be achieved without the data. Demographic data (such as name, address and date of birth) are essential for these projects to ensure under coverage and over coverage within the individual data sources are dealt with appropriately. All requests for data are scrutinised to ensure the principle of data minimisation is applied and only data required for the purposes set out will be requested and processed.

ONS does not consider there to be any moral or ethical issues raised by the proposed dissemination. An internal Data Protection Impact Assessment (DPIA) indicates this process poses little risk of potential harm to the public. ONS considers the primary risk of any data share of this type to be the identification of individuals through either misuse by persons within the organisation or by a loss of data in transfer. Therefore, to protect against these risks, ONS employs rigours disclosure controls and access restrictions – ensuring that physical, technical, procedural and personnel security is kept to the highest and most up to date standards. To reduce the risk of data loss, data will be transferred using an agreed, secure, electronic transfer facility which adheres to Government requirements and assurance. An in-depth description of the security capabilities of the environment in which the data is injected, stored, linked and analysed is detailed below under the heading ‘Data Environment’.

Population Statistics Division

NHS Digital previously supplied CHRIS data and Patient Register (NHAIS) data to ONS for the purposes of estimating internal migration in England and Wales, and cross border flows to and from Scotland and Northern Ireland. Patient Register (NHAIS) data are due to be decommissioned and as such ONS need to assess its proposed replacement (PDS). The Patient Register data, in addition to internal migration estimates, are also used in the local authority distribution of international migrants for the mid-year population estimates and in the small area population estimates. Internal migration estimates are national statistics and a key component in population estimates and projections, also national statistics, which are used extensively throughout government to allocate funds. Under Section 5 of the Census Act 1920, ONS have a duty to ‘collect and publish any available statistical information with respect to the number and condition of the population in the interval between one census and another’ and ‘may make arrangements with any Government Department or local authority for the purposes of acquiring any materials or information necessary for the purposes’.

The data will be used in conjunction with other administrative data for estimating internal and international migration, the local authority distribution of international migrants component of change for the mid-year estimates and small area population estimates within England and Wales and estimating migration between England and Wales, Scotland and Northern Ireland. In doing so, it may be combined with other data sources to improve accuracy and quality of estimates. For instance higher education student records obtained from the Higher Education Statistics Agency (HESA) to enhance information on the movement of students.

Census Transformation Programme

The system for providing population and socio-demographic statistics in England and Wales has been built around having a ten-yearly census. The census provides a population count at a point in time and enables a wide range of socio-demographic statistics to be produced for a range of small geographic areas.

The census provides three broad categories of information:

· Population and housing estimates: counts of the population by age and sex, and the number of housing units.

· Population structures: households, families and household relationships.

· Population characteristics: e.g. ethnic groups, health, qualifications and employment.

These statistics are produced for geographies ranging from England and Wales as a whole down to Output Areas (125 households on average) and for very small population groups, such as some ethnic groups and religious communities. As well as the direct census outputs, the census is the benchmark for the population estimates between censuses, for household and population projections and used as a denominator for numerous other statistics. This brings additional benefits which are delivered in the years between Censuses. NHS England currently uses population statistics to allocate billions of pounds to local areas using funding formulae.

In May 2010 and ahead of the census in 2011, the UK Statistics Authority asked ONS to begin a review of the future provision of population statistics in England and Wales in order to inform Government and Parliament about the options for the next census. ONS launched the Beyond 2011 Programme of research and reviews, including a major public consultation on the two leading options at the end of 2013.

In March 2014, the National Statistician recommended:

To the Board of the UK Statistics Authority that future provision of population statistics and the next census should be through:

· “An online census of all households and communal establishments in England and Wales in 2021 … recognis[ing] that special care would need to be taken to support those who are unable to complete the census online.

· Increased use of administrative data and surveys in order to enhance the statistics from the 2021 Census and improve annual statistics between censuses.”

This would make the best use of all available data to provide the population statistics which England and Wales require and offer a springboard to the greater use of administrative data and annual surveys in the future.

The Government welcomed the recommendation, and stating their position for the future of the census in England and Wales:

‘Our ambition is that censuses after 2021 will be conducted using other sources of data and providing more timely statistical information. However, any final decision on moving to the use only of administrative data beyond 2021 will be dependent on the dual running sufficiently validating the perceived feasibility of that approach. In the period up to 2021 UKSA’s plans should include ensuring that adequate research into the use of administrative data and surveys is carried out to enable a decision about the future methodology for capturing population and census data.’ - Government’s response to the National Statistician’s recommendation, 18 July 2014.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

No one dataset in its’ own right can be used to produce a reliable estimate of the size of the usually resident population because, for example, the population registered with a GP is not the same as the usual resident population. The PDS data specified to replace the flow ONS currently receives would provide information about the timing and nature of an individual's interactions with this system. This 'activity' data can be used by ONS to determine whether a record appears to be 'active' or 'inactive' for statistical purposes. This can then be used to improve the quality of population statistics through helping to address issues with definitional differences between administrative data and population definitions and time lags. Research outputs produce aggregated statistics and are subject to the same disclosure control requirements as described by Population Statistics Division.

There is no common identifier that can be used to link individuals’ records across these datasets and therefore ONS need access to identifiable record level data (including NHS number, dates of birth, sex, Full name, addresses and postcodes) to link the datasets and establish the aforementioned SPD. This allows ONS to draw strength across multiple datasets to improve quality and methods to estimate the size of the population and their characteristics. Linkage of identifiable data is needed to support the 2021 Census and provide evidence for the annual assessment of progress towards the Government's ambition beyond 2021. This linkage of identifiable data is required to support the 2021 Census and work towards fulfilling the Government's ambition to conduct future censuses using other sources, while ensuring that population statistics in the future will continue to meet the needs of users e.g. for resource allocation, service provision and planning.

Identifiable data is required to be able to link to other admin data sources, however no clinical data is being requested.

Name variables have been included because they are key variables that enable the linking of PDS data to other administrative data sources to produce Admin Data Based Population Estimates. The Patient Register Extract is currently a key data source used by the Census Transformation Programme (CTP) to produce Admin Data Based Population Estimates, with this being shut down a full understanding of the PDS Stocks data is required to assess its suitability as a replacement. If ONS cannot link administrative sources they cannot identify potential double counting or cases which do not meet their usually-resident population definition

In addition to replacing the CHRIS dataset, PDS has been proposed by NHS Digital as a replacement dataset for the NHAIS Patient Register extract that ONS currently receive. PDS has been linked to NHAIS using the NHS number as the data currently held allows ONS to initially assess the data for this purpose and is in accordance with permitted use. However, the numbers of records on NHAIS and PDS datasets are very different and ONS need to understand why a record may appear on one dataset and not the other. Research into this has begun but ONS are hampered in their investigations due to the lack of name information (received on NHAIS), which prevents further data linkage that may uncover characteristics of those not present on both datasets. If ONS cannot understand the root causes of the differences then ONS cannot then take account of them in their methodologies. This could result in ONS not being able to adopt PDS as a fit for purpose replacement for NHAIS and subsequently have a need for NHAIS data in 2019 and beyond, due to the longitudinal nature of their methods requiring more than one year of data. It may also result in delays to planned changes in methodology as ONS would be unable to link from PDS to other sources where name is required, for example within a component of mid-year population estimates.

Data Environment

The protection of data received from partners is very important to ONS and significant investment, activity and assurance is undertaken to ensure this data is secured throughout the lifecycle from ingest to processing and export. ONS are developing advanced approaches that enable improved statistical analytical capabilities including the linking and matching of personally identifiable information, while maintaining and enhancing procedural, personnel, physical and technological security protections that provide assurance to internal stakeholders and external partners. A developing data analysis environment, the Data Access Platform (DAP), will support this as ONS moves away from the Statistical Research Environment for our analysis work.

Data security for storage and linkage of the data will be provided with an assured ONS data analysis environment (DAP) that includes the following elements of security control:

• Need To Know applied through user account access and management

• Controlled ingest and export of data into/out from the environment

• Controlled account access using unique credentials based on job role

• Logged and monitored access of user activity within the environment

• Secure build configuration for infrastructure, including cloud services

• Vulnerability tested infrastructure with appropriate remediation and patching

• Compliance checks against security enforcing controls

• Architectural review against standards and best practice

• Staff security cleared to the appropriate level based on their supervised and/or unsupervised access to sensitive data in accordance with ONS clearance policies and data access processes

• Education and awareness of environment users covering security policies and secure working practices

• Operational support processes to securely manage the environment

• Risk assessment to identify security risks and mitigation actions to reduce this risk.

Following policy specified by the ONS Chief Security Officer, users will be granted supervised or unsupervised access following a clearance application. The ONS Information Asset Owner (IAO) grants access and a list of all authorised users is available on request.

With reasonable notice, periodic written/verbal checks may be conducted by an authorised employee of NHS Digital to confirm compliance with this DSA.

ONS will keep a record of any processing of Personal Data and will provide a copy of such record to NHS Digital on request.

ONS will not transfer or permit the transfer of the Data to any territory outside the UK without the prior written consent of NHS Digital.

Migration – Business Case for 2018/19

The Centre for International Migration is leading on work which will begin to put administrative data at the core of migration statistics in 2019. This programme of work forms part of a larger Government Statistical Service (GSS) transformation plan which is recognised in the Home Affairs Select Committee’s report and government response.

The Personal Demographic Service (PDS) data would form an integral part of plans to put administrative data at the core of migration statistics. The data will help develop an understanding of international migration and improved migration estimates at local level. Improved statistics, at a more granular level, will enable more effective decision making, policy development and evaluation and resource allocation at local level. Receiving PDS data will allow migration statistics to:

1. Build on ONS' work identifying migrant interactions within the health system as a sign of activity and the impact of migration on the health sector. This will be achieved by linking to other health datasets including the Hospital Episode Statistics and the Improving Access to Psychological Therapies dataset.

2. Compare signs of arrival, activity and departures by linking PDS to other public-sector datasets.

Main publication dates are as follows:

Internal migration – Annually – June

Internal migration statistics are published at local authority level by age and sex. They have wide use by local authorities and academics, including feeding into alternative population projections models and subsequent resource allocation planning. Mid-year estimates – Annually – June, with lower level geography releases after this until Small Area Population Estimates are released in November.

National Population projections – normally published at the end of October. Releases have traditionally been every other year. Following the national projections, there are sub-national releases between national releases.

Internal migration estimates are a key component of population estimates and population projections, which have wide and important use in the UK. Estimates are used in resource allocation from Central Government to local government and health authorities as well as in denominators for other statistics across government, which feed into policy decisions. Projections are used to determine future provision of public services such as schools and hospitals. At the local level these statistics are used to determine the types of services which are needed, for example a hospital may use them in determining whether or not to alter the level of provision of maternity or geriatric services.

Population projections and estimates are produced for CCGs and local authorities. Population estimates are also produced for output areas, parliamentary constituencies and other small area types.

Census Transformation Programme (CTP)

CTP has committed to publishing regular annual Administrative Data Research Outputs on the population, including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015 and included pseudonymously linked multiple datasets (including NHS Patient Register data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013 and 2014.

The aim of these research outputs is to:

• Update users on the progress with administrative data and to seek feedback with the aim of improving the methods used.

• Help the process of working with data suppliers to improve data quality for statistical purposes

ONS will aim to develop them in both method and content in the run up to the 2021 Census, and ultimately compare them with results from the 2021 Census. ONS will also expand on the range of topics and granularity published each year.

ONS recognise the need for continued development of their methodology, so future releases will also include outputs based on future developments which will allow feedback to be taken on board from users, new data that becomes available, and alternative techniques to produce population statistics.

A new series was introduced in 2016 to include these developments which showed improvements to the methodology. Additionally, subject to satisfactory data access and quality, ONS also aim to release population statistics at more detailed levels, and outputs about other topics or characteristics of the population (other than age and sex) such as qualifications, personal or household income, and ethnicity, as well as on the number and the size and composition of households. ONS also plan to present their research into the development of a methodology to estimate and adjust for coverage error in the SPD.

In the spring of each year, starting in 2016, ONS will publish an assessment of progress towards the Government’s ambition to produce population statistics from administrative data after 2021.

The Census Transformation Programme (CTP) has continued research from the Beyond 2011 Programme into the use of administrative data and surveys to assess whether in ONS’ view the Government’s ambition can be realised. To that end, CTP has committed to publishing an annual assessment of progress towards the Government’s ambition and regular Administrative Data Research Outputs on the population, crucially including estimates of the size of the population produced using administrative data. The first such outputs were published in October 2015, based on pseudonymously linking multiple administrative datasets (including NHS Patient Registration Data, DWP/HMRC Customer Information System data and higher education data) to produce a Statistical Population Dataset (SPD). These outputs are produced annually, the most recent being October 2016. SPD population estimates have been produced for each local authority, by five-year age groups and sex for 2011, 2013, 2014 and 2015.

NHAIS feeds into annual releases for mid-year population estimates, internal migration estimates and small area population estimates (including clinical commissioning groups); through these estimates, NHAIS then indirectly feeds into the national population projections and the subnational population projections (including clinical commissioning groups) which are produced every two years. These statistics have onward use in resource allocation for example in the distribution of funds from central to local government.

Record level data will be held securely within ONS. The data will be held in the accredited Statistical Research Environment (SRE) located at ONS premises. The environment has been specifically designed to support the linkage of personal data and has security measures in place to mitigate the associated risks. NHS digital were consulted during the design and build of this facility and have continued to be involved in its oversight since it became operational. Only named researchers have access to SRE and it is not possible to access a printer, disks, internet or rest of the ONS network whilst in this room. It is a secure room that requires additional security clearance to gain access to. The approach taken to manage data is described in the ONS's safeguarding data for research policy.

Statistical Design and Research

Since the last Data Access Request Service was agreed, the following developments have been made:

• ONS have conducted quality assurance analysis on the dataset, which has fed into internal report on the dataset.

• ONS have received Name variables from NHS-Digital as part of the extract received which now feeds into analysis.

• PDS has been used as a tool to quality assure the linkage of address data between PR and CIS in a previous SPD publication.

• PDS has been used as for the quality assurance of Births and Deaths Registration data which will feed into the migration publication to be released by ONS in late autumn 2018.

• PDS has primarily been used to link to other datasets and develop an iterative methodology to produce population and migration estimates. Early parts of this work were presented at the British Society of Population Studies (BSPS) conference earlier this year.

Going forward, within SDR one of the key uses of PDS will be continuing to link the data to a range of other datasets at record level to develop a methodology to produce population and migration estimates by sex and age to levels of geography currently published by the official Population Estimates going forward.

ONS have recently raised a request for a number of additional variables to be delivered going forward however discussions surrounding the acquisition of these variables is ongoing so no further update can be provided on specific variables. The key variables that have been requested are those which provide some form of identification which is descriptive of a person and any variable which would highlight activity.

Additionally, it is likely be used to pick up the demographic information that is missing on other datasets, for example HES and IAPT, to allow for easier, more consistent linkage.

Census Statistical Outputs Design

Census Statistical Outputs Design are hoping to use the PDS to aid in the imputation and quality assurance of Census, particularly of people resident in communal establishments such as care homes and mental health establishments. This mirrors what was done in 2011 using the PR. Response to Census in communal establishments is variable, and it’s not always clear where non-respondents are located due to unreliable administrative data estimates about the care homes themselves (referring to total capacity rather than occupied capacity). It is hoped that if a person is usually resident in a care home, the chances of them not appearing on the PDS will be small. Therefore, estimates of currently occupied beds in care homes derived from the PDS linked to a list of identified care homes and then compared to Census responses for that care home will identify approximate numbers of people missing from that care home’s Census responses. Demographic information from the PDS for that care home can then be used to determine appropriate types of donor records to impute missing responses. Work to develop this approach is ongoing, with a test of the approach to be conducted during the 2019 Rehearsal.

Migration Statistics Division

The Centre for International Migration have linked the PDS to HMRC’s Migrant Worker Scan (MWS). This has enabled comparisons of potential arrival and registration dates between the two sources and in turn has tested assumptions on lag between arrival and registration with a GP. Other quality work includes how many ‘new migrants’ on the MWS are seen in PDS. This is part of ONS’ wider work to link different admin data sources together and test assumptions around putting administrative data at the core of migration statistics. This work is planned to continue going forward.