1. Overview of Census 2021 National Statistics Accreditation, Phase 2

The Office for Statistics Regulation (OSR) is assessing the 2021 and 2022 Censuses in the UK. These are conducted by the Office for National Statistics (ONS), National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA), in England and Wales, Scotland and Northern Ireland respectively.

The purpose of the assessment is to inform the OSR recommendation on whether Census 2021 outputs should be designated as National Statistics, in accordance with the requirements of the Statistics and Registration Service Act 2007, when they are first released.

This report provides an update on our progress to gain National Statistics accreditation and will be used as part of the evidence base by the OSR when assessing our compliance with the Code of Practice for Statistics (referred to as the Code in this article). Compliance with the Code provides users and the public confidence that the Census 2021 statistics are of public value, are high quality and are produced by an organisation that is trustworthy.


In June 2019, we published our initial report How the ONS is ensuring the 2021 Census will serve the public, which was a first step towards measuring progress against the three pillars underpinning the Code: trustworthiness, quality and value.

In October 2019, the OSR published its first report 2021 Censuses in the UK - Preliminary findings, which detailed preliminary findings from the assessment to that point. The report set out a number of actionable findings from Phase 1, which the ONS, NRS and NISRA were required to address to improve compliance with the Code.

In June 2020, we published our initial Response to actionable findings from Phase 1 of the National Statistics Accreditation, which describes how the ONS is building upon existing plans and practices to address the OSR recommendations, helping to deliver a high-quality census for users.

In September 2020, the OSR published a letter to the ONS, which reviewed the actions the ONS has taken to address the actionable findings from Phase 1. The OSR acknowledged the noteworthy activities being undertaken and identified some areas where further action is needed.

NISRA have also published a similar report for Phase 2 of the National Statistics accreditation. A report from NRS will follow in winter 2021 in line with their census being in March 2022.

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2. User engagement and question development (actionable findings 1, 2 and 3)

Finding 1: Accessibility of research and information

Census offices should consider the accessibility of research and other census information on their websites and consider aligning website design and content where possible to provide a common user experience.


There is ongoing engagement between the Office for National Statistics (ONS), National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA) in this area. In September 2020, the three census offices and the digital transformation consultancy enlisted by NRS to deliver the new Scotland's Census outputs website attended a workshop. This enabled us to:

  • gain a greater insight on the activities and plans around the Census website of each office

  • identify opportunities for aligning website design and content to provide a common user experience, where possible and practical

  • reinforce the commitment to improve signposting across the three websites on important topics of interest to users

ONS website improvements

The ONS has formed the Website Task and Finish Group to review and improve the Census home page and Census and Data Collection Transformation Programme (CDCTP) pages on the ONS website.

Initially, we co-ordinated a review of the Census Data Collection Transformation Programme pages on the ONS website, identifying any changes required. Alongside this, we identified improvements to a number of higher-level and navigational pages to simplify these pages and make them easier to navigate.

Next, we commissioned a piece of user research to gain a better understanding of the user need for information. We used these results and analytics for the most viewed pages to identify further improvements to be made to improve navigation, signposting and accessibility.

Improving the navigation

The website revisions include an update to the tiles on the Census home page to make it easier for users with different needs to navigate to what they need. The revisions include:

  • removing unnecessary tiles

  • adding new tiles to link to the new "Census news", "Taking part in and supporting the census" and "Censuses in Northern Ireland and Scotland" pages

  • updating content of links and tiles to make the purposes of each page clearer, especially census transformation

The tiles on the Census transformation page have been organised to support easier user navigation and to ensure content has a more logical structure. The changes include:

  • removing unnecessary tiles (for example, there are many that were added for prominence but are already linked from their respective areas)

  • deleting out of date and unnecessary pages, for example, a "Progress and development" area, which is no longer required

  • reordering tiles and updating content to better explain the purpose of each page

The Question development page has been refreshed to support easier user navigation and to ensure content has a more logical structure. The changes include:

Other changes to improve navigation and accessibility include the following.

Adding links to other most commonly used Census pages to encourage onward user journeys from several pages: About the Census, Census milestones and Legislation and policy.

Updating the Census design tile page to make the tile titles and summaries clearer and more concise. We also reordered the tiles to make the most recent publication nearer the top and removed a tile that linked to an outdated PDF. A link to the PDF has been added to the statistical design report instead.

Updating the Overview of our design plans for Census 2021 page to bring the links nearer the top, to add section headings for easier navigation, and add links to other relevant pages to encourage onward user journeys.

All pages and tiles mentioned have had clear and consistent keywords added to them.

New pages and content

Following an initial review of existing structure and content, six new pages have been created:

Census news is a prominent news page that will be updated regularly with our progress towards Census 2021. The first update was provided to coincide with the 1 October 2020 publications, which set out our Census Statistical Design and operational response to COVID-19, building on our learning from the 2019 Collection Rehearsal evaluation. These publications seek to provide better visibility and access to research and information about the census planning.

Censuses in Northern Ireland and Scotland is a navigational page to direct users looking for information on the Northern Ireland and Scotland censuses, to the relevant pages on the Northern Ireland Statistics Research Agency and National Records of Scotland websites respectively.

Taking part in and supporting the census is a navigational page to direct users looking for information on taking part in the census to the census public campaign website. Also, it was created to direct local authority and community group users wanting to know how they can support the census, to the relevant page on the campaign website.

Census events page is an area that provides information on some of the census events the Office for National Statistics (ONS) has held or been involved with as part of our planning for Census 2021 and beyond.

Census and Data Collection Transformation Programme is a navigational page that sits within the Programmes and Projects area of the ONS site, aimed at joining together the currently separate Census Transformation and Data Collection Transformation areas.

About the Census and Data Collection Transformation Programme is a page that provides a brief overview on our programme dedicated to transforming the census and our data collection capabilities.

Next steps

We acknowledge there could be increased visits to the ONS website during the operational phase of Census 2021, most likely from respondents. We are considering how to better meet their needs and improve the user journey between the ONS website and the census public campaign website. We will commission user research to help with this. Improvements could include updating pages most likely to be visited and updating the homepage.

We will also focus on updating our transformation content ahead of our 2023 recommendation on the future of the census and the social statistics system.

Finding 2: Transparency of census questions and guidance

Census offices should be open and transparent on their decision-making processes and in their decisions on census questions and guidance, particularly in relation to any areas of contention.


Census questions

The questions and response options for Census 2021 have been finalised through the census secondary legislation, the Census (England and Wales) Order 2020 and Census Regulations for England and for Wales, and cannot be changed.

We have completed the suite of question development reports, which explain the research, testing and evaluation carried out on question design, and these have now been published. These cover the following topics:

In December 2020, we published details of how we have developed and implemented Search-as-you-type and address look-up functionality for Census 2021.

We are updating the Census news page and contacting stakeholders via email to alert them to the publications.

Changes to guidance on electronic questionnaire because of COVID-19

Our Updates to Census 2021 online questionnaire guidance article, published in February 2021, explains how we developed and tested additional guidance to support respondents in answering Census 2021 questions in the context of the coronavirus (COVID-19) pandemic.

Alongside this we will also update the existing summary of testing to include tests carried out since it was initially published. This page will also include links back to the testing reports. All tests undertaken are clearly referenced in the question development reports and a summary of tests used to finalise the topic are included as an annex in each.

Our approach to the guidance is harmonised with the Northern Ireland 2021 Census approach. We have worked collaboratively with NISRA on the question guidance in relation to COVID-19. This is to ensure that we are providing the same steer to respondents in relation to circumstances changing because of COVID-19.

Scotland's Census will take place in 2022, so no updates have been made to their question guidance.

We continue to work closely with colleagues in Northern Ireland and Scotland to maximise harmonisation of outputs across the UK.

Other guidance

In February 2021, we finalised and published our work on the Final guidance for the question "What is your sex?", having previously discussed the work and methodology with the Methodology Assurance Review Panel. We have notified stakeholders the methodology article and guidance has been published.

Finding 3: Focus on the needs of UK census data users

We consider that there should be more focus on the needs of census users at a UK level, in three areas.

Finding 3.1: Engagement and activities

Census offices should consider how best to engage with users and stakeholders of UK census data and statistics users, and coordinate activities as appropriate.


In addition to the initiatives explained in Response to actionable findings from Phase 1 of the National Statistics Accreditation report (see Actionable finding 3), the three UK census offices have continued to work together to co-ordinate activities.

The UK census data working group, which has representation from the three UK census offices and the Welsh Government, continues to meet monthly and progress activities in this area. The group intend to draw on expertise across the wider GSS and others to explore ways that might improve engagement with UK census data and statistics users.

A new User Working Group for UK Census 2021 and 2022 Data has been set up. This has been set up with a purpose to provide a forum for sharing information and feedback between the UK census offices and UK census data users. The group will inform development of a dissemination approach that maximises the benefit that can be gained from providing UK census outputs. The working group will share information on its activities to increase the visibility of its work.

The three UK census offices continue to attend and participate in each other's stakeholder and user events where relevant and practical. The ONS attended NRS Outputs stakeholder engagement events in November 2020 and January 2021. NISRA and NRS attended the ONS series of user webinars (see Webinars in Section 9: Stakeholder engagement and feedback) held in November and December 2020.

The UK harmonisation page published in response to this finding in 2020 is reviewed regularly and updated when necessary. A link to this page has been added to the About the Census, as part of the work to enhance the ONS website.

Finding 3.2: Decision-making and transparency

Census offices should be clear about the impact of country-specific decision-making for UK census data and statistics and work together to provide greater transparency around their plans and decision-making in meeting the needs of users interested in UK census outputs.


In July 2020, the Scottish Government announced that Scotland's Census will now take place in March 2022. The statement of agreement between the National Statistician and the Registrar Generals for Scotland and Northern Ireland about the conduct of the 2021 Censuses in the UK has been revised to reflect this. It has also been updated to reflect changes because of the UK's exit from the European Union.

We published a progress update for November 2020. The update is structured around three broad aspects of Census 2021 that are a strong focus of harmonisation, namely outputs, census procedures and governance. Within each section, clear information is provided highlighting to users the considerable progress made to date on harmonisation. We also provide:

  • examples of how decisions are made taking into account UK data user needs

  • a list of all harmonisation working groups demonstrating the breadth of harmonisation work the three census offices undertake

To support harmonisation activities and co-ordinate engagement with users of UK data, we meet regularly with National Records of Scotland (NRS), Northern Ireland Statistics and Research Agency (NISRA) and Welsh Government. We are working closely with NRS and NISRA to ensure we continue to produce the UK-wide population statistics necessary and will engage with users through the new User Working Group for UK Census 2021 and 2022 Data. This has been set up with a purpose to provide a forum for sharing information and feedback between the UK census offices and UK census data users. The group will inform development of a dissemination approach that maximises the benefit that can be gained from providing UK census outputs.

The census offices across the UK are working collaboratively on how to handle the related impacts of different census reference dates on UK Outputs and the wider Population Statistics system, as well the impacts of COVID-19 on particular census topics.

We will also ensure that harmonisation information is more easily accessible to users when outputs are made available. Updates on UK harmonisation can be found on the harmonisation web page.

Finding 3.3: Harmonisation

Census offices should provide users, stakeholders and decision-makers with information on harmonisation of census questions and the impact on outputs at UK level to help inform users and support decision making.


Work is ongoing to produce a clear understanding of the harmonisation of Census 2021 questions across the UK; this includes highlighting where differences exist, the underlying reasons, and the resultant effect on UK-level outputs. This work could not be completed until the respective Census Orders and Census Regulations for each part of the UK had become law, upon which the Census 2021 questions would be finalised.

With the legislation in place, the three census offices continue to work together to review question and outputs harmonisation. The expectation is for this information to be published by early 2022, so data users are fully informed at the earliest opportunity and in advance of the publication of first census outputs in 2022.

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3. Methods, data and quality management (actionable findings 4 and 5)

Finding 4: Strengths and limitations of data sources

Census offices should build their awareness of the relative strengths and limitations of any administrative, commercial or other data sources used in the production of census outputs, by regular engagement with suppliers. This should be undertaken on an ongoing basis and as part of a normal way of working.


Our statistical design publication explains how we are making greater use than ever before of the administrative data collected by public and some private sector organisations. These data are being used throughout to help drive up census quality, to produce new outputs by integrating census and administrative data, and to help quality assure the statistics before release.

See Use of administrative data in Census 2021 in Section 1: Overview in our statistical design publication for how we are planning to use administrative data.

The Office for National Statistics (ONS) have developed a quality framework for the use of administrative data across the office, which will be used as the basis to report publicly. As the Census is just one user of these data, the approach is to set out the quality and appropriateness of sources across the office. An article, including the quality framework, was presented to the Methodology Assurance Review Panel and will be published on UK Statistics Authority website by the end of March 2021.

Finding 5: Availability of methodology and quality assurance information

Census offices should make information on the methodology and quality assurance arrangements available to users at the earliest opportunity.


Our Statistical design for Census 2021, England and Wales article, published October 2020, explains our end-to-end statistical design to ensure Census 2021 results are of high quality and are fit for purpose. It sets out our approach to ensuring that we count everyone and only count them once. It also describes methods that have been used in the past (and enhancements to these) to:

  • make use of the increased availability of operational management information to help maximise response rates

  • ensure the best possible estimates building upon our Census Coverage Survey approach with increased use of administrative data to help identify and deal with issues

To explain the statistical design for Census 2021 to users, we delivered a series of webinars in November and December 2020 (see Webinars in Section 9: Stakeholder engagement and feedback).

One of the webinars, Addressing for Census 2021 was also presented earlier in 2020, over two sessions, to 300 local authority users.

We have worked with the Government Statistical Service (GSS) website owners to get a new set of general ONS Methodology pages published, which include links to the census methods.

We have also developed additional contingency plans for a range of scenarios, for example, a lower than expected response as experienced in New Zealand in 2018 and to respond to the coronavirus (COVID-19) pandemic and other unforeseen circumstances.

We presented some initial ideas to the Methodology Assurance Review Panel (MARP), and will be discussing these fully with the MARP in early 2021. We are also exploring ways to make our methodologies more accessible beyond the detailed MARP papers that have been published.

In January 2020, we published an initial proposal for the approach and processes for assuring the quality of the 2021 Census data and invited comments from users of the census results.

To help develop that initial proposal, we have been working with our local authority users to refine our approach to quality assuring the results. See Section 8: Annex: Quality assurance approach for Census 2021 of the Statistical design for Census 2021, England and Wales, published on 1 October 2020. This explains how the Local Authority Quality Assurance Working Group (LAQAWG) has influenced our plans for quality assuring Census 2021.

The Quality assuring the Census 2021 results webinar held in December 2020 provided further insight into checks we will carry out to provide users with the confidence to use the statistics as the basis of making decisions. The aims of the webinar were to:

  • explain how the quality assurance of data contributes to the overall quality of the census results

  • describe how we will assure both the census processes and the final estimates

  • share our plans for comparing the census results with other sources of data

  • invite suggestions of further checks or information on quality that should be published

The Quality assurance approach has been reviewed and evaluated by the Methodological Assurance Review Panel (MARP).

The ONS administers the UK Quality Assurance Harmonisation Working Group to share plans and collaborate with the three UK census offices.

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4. Planning, management and ways of working (actionable findings 3.2, 6 and 7)

Finding 3: Focus on the needs of UK census data users

Finding 3.2: Decision-making and transparency

Census offices should be clear about the impact of country-specific decision-making for UK census data and statistics and work together to provide greater transparency around their plans and decision-making in meeting the needs of users interested in UK census outputs.


In the User engagement and question development section under "Finding 3: Focus on the needs of UK census data users".

Finding 6: Census milestones

Census offices should provide users with an indication of future census milestones - including future user engagement opportunities, publication of further research or reporting, and legislative milestones - to provide an added level of transparency and support trustworthiness and public confidence.


The Census milestones page has been updated to provide:

  • details of engagement opportunities

  • status updates on completed milestones and links to publications, where appropriate

  • a link to the Events page to enable users to see previous, present and future engagement opportunities

Finding 7: Assurance mechanisms

Census offices should be clear to users what assurance mechanisms are in place and be open about identified areas for improvement in a way that is proportionate and accessible to users.


The assurance page published in 2020 remains relevant. This explains the integrated approach we use to assure our work on the programme based on the "three lines of defence" model.

It has been updated to include a link to the 2019 collection rehearsal evaluation report for Census 2021, England and Wales published on 1 October 2020.

Other assurance mechanisms are in place, explained in this section.

Infrastructure and Projects Authority (IPA) Gateway Reviews

These are short, focussed reviews that take place at important decision points. Gateway reviews are conducted on behalf of the Senior Responsible Owner (SRO) by a team of experienced practitioners, independent of the project team.

These reviews only provide a snapshot of a project at the time and recommendations are based on the interviews undertaken and evidence presented. They are intended to be supportive and forward-looking and will take future plans into account, but only as future intentions, rather than actualities.

Coronavirus (COVID-19) Readiness Assessments

We have put into place a series of COVID-19 Readiness Assessments throughout this year, to check we remain on track to deliver the census despite the wider context of the COVID-19 pandemic. The most recent of these took place on 1 December 2020.

Census risk management

Within the census programme, we follow corporate guidance to manage our risks, ensuring we adhere to best practice. We aim to embrace the importance of managing our risks in a vigilant and disciplined way to assist in timely decision-making to enable successful programme delivery.

Methodology Assurance Review Panel

The external Census Methodological Assurance Review Panel (MARP) has been set up to undertake a review of methods and research associated with Census 2021. The reviews will provide assurance to the National Statistician that:

  • the statistics resulting from the Census 2021 will meet the Code of Practice for Statistics and therefore can be badged as National Statistics

  • the census is methodologically robust

  • the evidence to show whether an Administrative Data Census approach to census-taking is valid and enables the government to decide after 2021 about the future of the census

The reviews started in 2018 and are planned to take place up to 2023.

The panel is chaired by Sir Bernard Silverman. Other confirmed panel members are:

  • Oliver Duke-Williams, Assistant Professor in Digital Information Studies, University College London

  • Dr Nik Lomax, School of Geography, University of Leeds

  • Natalie Shlomo, Professor of Social Statistics, University of Manchester

  • David Martin, Professor of Geography, University of Southampton

The minutes and papers from the external panel are published on the UK Statistics Authority website. Past papers presented at the panel will be published in 2020 with ongoing publication of future papers.

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5. Effect of the coronavirus (COVID-19) on the Census 2021

This section, and the subsequent sections, has been included to demonstrate compliance with the three pillars of the Code of Practice for Statistics.

In our statement, published in January 2021, we explain the importance of running the census in 2021 and describe how we are ensuring everyone can be safely counted in the context of the coronavirus (COVID-19) pandemic.

As explained in our Response to actionable findings from Phase 1 of the National Statistics Accreditation, the ongoing coronavirus (COVID-19) pandemic presents a challenge to the Office for National Statistics (ONS), National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA). Each UK census office continues to work closely to assess the impact on the Census programmes across the UK.

The ONS and NISRA will continue to deliver Census 2021 in March 2021. In July 2020, the Scottish Government announced that to secure high-quality outputs Scotland's Census will take place in March 2022.

Impacts on operations

Our operational planning response to the coronavirus article focuses on how we have adapted our operational plans for Census 2021 in light of the coronavirus pandemic. It also covers the contingencies we are putting in place.

As the situation has evolved, our plans have continued to adapt, and continued assessments made to ensure the census collection operation is carried out safely. Updates on the approach were shared with Census Advisory Group members in January 2021.

Changes announced by Scotland have no direct operational impact on the Census in England and Wales.

Impacts on questions

See Changes to guidance on the electronic questionnaire in Section 2: User engagement and question development for details on the impact of the coronavirus.

Changes announced by Scotland have no direct impact on the Census 2021 questions in England and Wales.

Impacts on methods

Our statistical design publication explains a range of approaches we may take, should we need to, to ensure we deliver the high-quality census and population estimates needed for users and are confident these plans enable delivery of this (see Contingency planning in Section 4: Process and estimate of the statistical design publication).

Changes announced by Scotland have no direct impact on the methods being used for Census 2021 in England and Wales.

Impacts on outputs

The Census 2021 data we collect will be fundamental to our understanding of the impact of the pandemic on our society. It will inform policy for years to come and ensure the big decisions facing the country are based on the best information possible. The 2021 data will paint a picture of our population and our characteristics at this significant point in time. This snapshot will act as an essential baseline not only for measuring change after the pandemic but also for assessing the cumulative impacts of the pandemic, exit from the European Union and other crucial government policy initiatives, such as "levelling up".

Census 2021 has been designed as a primarily online census. Our design is simple, straightforward and the questions and questionnaire have undergone thorough testing and rehearsal. We are confident in the standard design of our census methodology and our standard approach to ensuring quality. We published Statistical design for Census 2021, England and Wales in October 2020 and our Approach and processes for assuring the quality of the 2021 Census data in January 2020.

However, our expectation is that the pandemic will present challenges to both our standard design and the data captured by some questions. We have been preparing statistical contingencies for many months to be able to deviate from our standard design where necessary and are revisiting our guidance and completion instructions to ensure clarity for respondents in areas where the pandemic may have had an impact on important characteristics, for example, the current location of students, so that user needs are met.

There are also specific topics, for example, travel to work, that will be impacted significantly by the pandemic and some populations who may no longer be present in England and Wales for whom we cannot automatically expect a response, for example, overseas students, workers from abroad.

Given the exaggerated rate of social change likely post-census there will be the need to supplement census data with other data to ensure future changes are fully captured, for example, our mid-year population estimates accurately capture the return of people from overseas. This is something we will work with users on and a new analytical work programme is likely to be necessary over the coming years to provide a full picture of the changing nature of society as we recover from the pandemic.

All the UK census offices are working closely together to understand the impacts on outputs because of the move in Scotland's Census date. There is likely to be some minor impacts on England and Wales outputs for workplace populations for some areas close to the border and out-of-term populations missing students studying in Scotland.

For UK data outputs there will be some impact on timing and scope. We will engage with users through the new User Working Group for UK Census 2021 and 2022 Data. This has been set up to ensure we are getting user input to inform decision making on UK census outputs. We aim to publish progress alongside other communications sharing information.

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6. Rehearsals

2019 Collection Rehearsal

The 2019 rehearsal took place between September 2019 and December 2019. The rehearsal provided an important opportunity for us to test the processes, systems and services we will need to use for Census 2021. It took place in four local authority areas:

  • Carlisle

  • Ceredigion

  • Hackney

  • Tower Hamlets

The 2019 Collection Rehearsal evaluation report for Census 2021, England and Wales details the main findings and lessons learned that we will be carrying forward to the main Census in 2021 from both the collection rehearsal (which covered households and communal establishments), and the Census Coverage Survey (CCS) rehearsal that immediately followed it.

2020 Processing and Outputs Rehearsal

The 2020 Processing and Outputs Rehearsal was a crucial opportunity to test the end-to-end flow of a large volume of data through the processing environment and into outputs for dissemination in a simulated live environment. Doing this was an important lesson learned from 2011.

The rehearsal was run in an agile way testing functionality as it became available. This approach allowed the rehearsal to continue when working patterns had to change as a result of the coronavirus (COVID-19). The rehearsal was a success and we learnt what worked well and where improvements could be made. It provided us with a detailed understanding of how our systems, built upon new technologies, and processes worked. The rehearsal has enabled us to build improvements in our programme of work.

Additional work will take place in early 2021 to finish testing some of the statistical rehearsal end-to-end methods (see Statistical methods rehearsal Section 10: Methods development).

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7. Legislation required for the Census 2021

As informed in our Response to actionable findings from Phase 1 of the National Statistics Accreditation published June 2020, all the legislation required for undertaking Census 2021 is now in place, a summary of which is published on our Legislation and policy page.

Information will also be provided on the Data Protection Impact Assessment (DPIA) and Human Rights Impact Assessment for Census 2021. The DPIA has now been completed and will be published on the ONS website in early 2021. The assessment:

  • looks at the aims and benefits of the census

  • how respondent data and operational data will be processed during the course of the census

  • identifies how the census meets the data protection principles

  • assesses the necessity and proportionality of the census

  • identifies the risks to processing personal data and how those risks are mitigated

Privacy information for respondents will be published on the census.gov.uk website and available to the public throughout the course of the census. A paper version of the privacy information will be provided alongside all paper questionnaires. Paper versions of the information will be available on request. Shorter versions of the information will be available in a variety of languages and in Braille. There will also be a British Sign Language video of the information, accessible from the census.gov.uk website.

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8. Achieving our quality targets and maximising response

Our statistical design publication explains our quality targets (see The statistical design in Section 1: Overview). It also explains how our respondent-centric approach will ensure that it is as easy as possible for people to respond however, and wherever, they wish to. This will aid us in meeting our quality targets.

There will be various methods of completion for Census 2021 such as, online questionnaire, paper questionnaire and telephone capture. See A digital-first census in Section 2: Design and build of our statistical design publication for more information on this.

Providing the right support and ensuring that everyone is aware of what they need to do is vital to ensuring that we meet our response targets. For the first time, the default mode of completion for Census 2021 will be via an online questionnaire.

We have made it easier for people to complete the census from any device. Paper questionnaires will be available to people that request them. Support will be available, via Census 2021 Support Centres, for those who wish to complete the census online but may need help to do so. People will be able to complete the census over the phone with trained staff via our free phone contact centre.

Developing our online help

The aim of our online help, which will go live in February 2021, is to answer any question that could interfere with a respondent's ability or willingness to engage with the census. We will give Welsh-speaking respondents the same opportunity to have accessible content and therefore the content is produced in both English and Welsh. Users will include the public, the Public Contact Centre advisors, Census Support Centre advisors and field staff.

Support centres for Census 2021

We are working alongside Good Things Foundation (GTF) to build a network of census support centres where people can get support to complete the census online, where it is safe to do so and in keeping with government guidance. This will help to ensure everyone has the chance to complete the census digitally across England and Wales.

To decide on the locations of census support centres for Census 2021 we analysed data from the 2011 Hard to Count Index (ONS), Indices of Multiple Deprivation, population data at local authority level and urban and city areas.

Working with GTF we were aiming to stand up a maximum of 700 centres in 293 local authorities. However, because of the negative impact of COVID-19 on the smaller providers, the number is likely to be less. These centres will be in various settings, such as community centres, housing association hubs and libraries. We will continue to monitor the situation across England and Wales to assess whether and where Census Support Centres can open to provide this service.

COVID-19 has had an impact on how we will approach Census Support Centres. A digital divide has been emphasised since the national and local lockdowns. GTF is exploring innovative delivery options for a COVID-19 world, such as assistance to complete online questionnaires with remote support, use of personal protective equipment (PPE) in centres and sharing data insights from their centre. These options are being considered alongside the ONS COVID-19 scenarios (see Section 3: Identifying the risks: scenario planning and potential impacts of the pandemic in the Statistical design publication), to work collaboratively to reshape the census support service for census 2021 if the current situation continues.

Help from within the community

We employed 300 engagement staff across England and Wales six months ahead of the census. Their role is to work with local communities focusing on communities where without extra engagement and conversation, census response rates may suffer. Their role is to raise awareness of the census, publicise it, address concerns and provide information and reassurance so people feel confident to complete the census. They will help people understand how the census makes a difference to everyone in their community, such as the planning and provision of education and medical facilities.

Census engagement managers (CEMs) are responsible for engaging with a wide range of communities in a local area to build trust and encourage participation in the census among communities that may face barriers to completion. This will be essential in helping make sure we get the response we need to make the census a success.

Community advisers (CAs), work alongside the CEMs. Their role is to engage with specific local communities whose members may not understand the importance of the census. In many cases, they will be using language skills appropriate to the communities they are working with.

COVID-19 has restricted the engagement activities of these staff because they have had to work almost entirely online and, on the phone, rather than face-to-face. During the operational period, they will help the public complete responses if possible. Physical assistance is unlikely to be possible, because of COVID-19, and so the engagement staff will need to look to assist people online or by phone.

We have launched our educational primary and secondary school programmes to support Census 2021 following the successful pilot of the Let's Count! programme during the 2019 rehearsal.

Schools across England and Wales are now able to sign up for our inclusive census educational programmes, which will enable the next generation to learn about the census and how it benefits their communities. All resources have been designed so they can be adapted and taught remotely. In addition, video lessons have been developed as ready to go resources to make this easier for schools to deliver during a national or local lockdown.

The primary school campaign Let's Count! is a cross-curricular programme designed to excite children and families alike about the census. With maths and statistics at its core and featuring the charismatic Counter Cats, the programme provides flexible lesson plans and interactive content across many topics.

We have also added two new lesson plans to the primary school campaign to bring the programme right up to date. An NHS lesson plan will champion the service and explore how census data plays a vital role in planning and funding for organisations like this. Additionally, an equality and representation lesson plan will highlight the importance of inclusivity within both the census and everyday life.

The census schools programme Let's Count! won the Award for STEM Educational Programme of the Year at the Wales STEM Awards. The awards aim to throw a spotlight on Wales' Science, Technology, Engineering and Mathematics (STEM) stars.

The Educational Programme of the Year Award goes to those who address the STEM diversity gap or skills shortage or inspire the next generation.

Secondary schools will also be able to take part in engaging activities. Students will explore why the census matters to them and their local communities, covering topics across the curriculum.

The programme aims to engage young people, empowering them to use their voices to encourage their families and community to complete the census. It will use real-world tasks to explore how data are used and influence decisions across society. The lesson content will inspire whole-school participation and link to curriculum subjects such as citizenship, Personal, Social, Health and Economic education, maths and history.

Publicity campaigns

It would be impossible to carry out a census without the co-operation of the public. Every household and each resident in a communal establishment in England and Wales is obliged by law to make a census return.

The ONS will, in close co-operation with the census offices in Northern Ireland and Scotland, deliver a communications campaign to encourage householders to complete their questionnaire. This will ensure that they know when and how to do so and will explain the purpose and value of the census and give reassurance about confidentiality and data security. This will include messages about the legal requirement to complete the census.

The goals of the census publicity campaign itself are to:

  • increase awareness of the census, understanding of what census is and how it relates to all audiences

  • increase motivation to proactively complete the census

  • increase awareness of, and trust in the ONS and the department's official statistics

We have designed our activity based on comprehensive audience insight, which will help determine the right messages, media and completion journey for different groups. This will help us to deliver an effective and efficient campaign.

To celebrate Census 2021 being the 22nd census of England and Wales, we will recognise the achievements of ordinary people who have done extraordinary things for the benefit of their communities.

We will award 22 bespoke purple plaques, in the brand colour of Census 2021, that can be placed in or on the winner's home, place of work or a community building.

Members of the public were able to nominate their community's heroes on the Census 2021 heroes webpage throughout December 2020. The competition will be judged by a panel of community champions, led by Gavin and Stacey star, Joanna Page.

An update for how the three UK census offices are harmonising on the publicity campaigns was published in January 2021.

Maximising response to Census 2021

Further to information provided in our Response to actionable findings from Phase 1 of the National Statistics Accreditation (see subheading Maximising response), our statistical design publication provides an update. See Identifying those who might need help in Section 2: Design and build and Section 3: Monitor and counter. The sections also explain how minimising variability in response is of equal importance.

The Maximising response in Census 2021 webinar held in December 2020 provided information on how we will maximise response rates for Census 2021 to include everyone and produce high-quality statistics. The aims of the webinar were to:

  • explore how we can model the expected patterns of returns and simulate different operational scenarios

  • demonstrate how we will identify shortfalls in response

  • explain how we will use live data to inform us of progress and respond flexibly where needed to enable us to meet our response targets

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9. Stakeholder engagement and feedback

We have provided comprehensive evidence of stakeholder engagement carried out for Census 2021 between 2015 and 2019 in our previous National Statistics reports:

  • How the Office for National Statistics is ensuring the 2021 Census will serve the public, published June 2019 - see Consultation and wider engagement in Section 4: Trustworthiness and see Public consultations, roadshows and meetings in Section 6: Value

  • Response to actionable findings from Phase 1 of the National Statistics Accreditation, published June 2020 -see Stakeholder engagement activities for Census 2021 in Section 3: Evidence of compliance with the code

The coronavirus (COVID-19) pandemic has impacted our ability to carry out some stakeholder engagement activities that we had planned. As a by-product we have expanded our use of innovative methods of digital communication to engage stakeholders. This has been remarkably effective and attendance at virtual meetings with stakeholders has been much higher, and much more frequent response engagement has been possible.

Engagement with local authorities and community groups

We engage with local authorities and community groups representing those people who may face barriers to completing the census. We have dedicated webpages for both local authorities and community groups. These set out how we want to work with them, provide information, links to more information and more detailed guidance to download.

Local authorities are important partners in delivering a successful data collection operation. They can help us with recruitment of staff, communication, local intelligence and quality assurance. They are also a sector that makes extensive use of census data so the ONS and local authorities working together is mutually beneficial. To ensure they are kept informed we send them regular newsletters and have held a series of on-line workshops over 2020 on different aspects of the census operation. 

We engage with community groups and leaders at a national and local level. By doing so, we are looking to gain trust and buy-in to the census from influential figures in communities. They can then promote the census and the need for completion in their communities. One way in which we do this is to explain the uses and benefits of census statistics to those groups. We focus on communities that face barriers to completing the census for cultural, motivational, understanding and ability reasons.

As well as maximising response to the census, we are also looking to broaden use of outputs.

We work with representatives of other sectors (central government, health, business and academia), through Census Advisory Groups and email updates for significant news, to ensure they are consulted on the census and their views taken on board in its design and delivery.

We have also established a Local Authority Quality Assurance Working Group with 17 local authorities. This is a useful forum for us to:

  • review our Census 2021 quality assurance plans

  • gain a better understanding of the actions that local authorities will take to understand the quality of our census estimates for their areas

  • gain a better understanding of what information they want us to provide on quality


We have delivered a series of webinars showcasing our plans for Census 2021. This provided stakeholders and users the opportunity to ask questions, give feedback and influence our future engagement activities to meet their needs.

These included a high-level introductory overview and "In Focus" sessions held in November and December 2020. The following sessions were delivered.

Designing for quality in Census 2021: An introductory session to discover how the census is expertly designed and delivered from start to finish to provide high-quality statistics for the public good.

Maximising response in Census 2021: An "In Focus" session to discover how we will maximise response rates for Census 2021 to include everyone and produce high-quality statistics.

Addressing for Census 2021: An "In Focus" session to discover how a comprehensive address frame has been created, and will be managed and updated, to ensure we count everyone in Census 2021.

Estimation and adjustment in Census 2021: An "In Focus" session to demonstrate how we estimate the population based on the Census and Census Coverage Survey, then create household information to match these estimates.

Quality assuring the Census 2021 results: An "In Focus" session to explore how we will ensure the census data are of high quality and fit for purpose.

Census 2021 outputs: An "In Focus" session to discover how we will use data from Census 2021 to produce timely, flexible and accessible outputs to meet a wide range of user needs.

In total across all webinars, there were over 700 attendees. 95% of attendees that provided feedback found the webinars somewhat or very useful to their role and organisations. When analysing their level of knowledge of the census pre- and post-webinars, the number of attendees answering that they had a higher level of knowledge of census increased by 20% after attending the webinar.

Most questions raised at the webinars centered around the impact of COVID-19 on the census and on particular topics and sub-groups. We explained the additional guidance being developed for some questions and the arrangements for engaging with users. There was also discussion about UK outputs as a result of the Scotland decision to carry out their census in 2022. The question and answers from the webinar will be circulated to attendees in February 2021.

Social media channels

We have grown our online presence through Census 2021 channels, launching brand new Instagram and LinkedIn accounts in addition to already existing Facebook, Twitter and YouTube accounts.

We post interesting and informative content to raise awareness of the upcoming census and keep the public up to date on all the latest census news. From revealing the census returns of famous faces from history, to uncovering fascinating statistics throughout the years, the social media channels provide a great opportunity to engage with the census.

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10. Methods development

The theory and principles of each statistical method are assured by subject experts at internal working groups and the Census Research Advisory Group (CRAG). Following this, the high-level principles of each method have been further assured at the Methodology Assurance Review Panel (MARP) to provide independent assurance on the robustness of methodology underpinning the Census 2021 estimates, including any use of administrative sources. Minutes and papers are published, and the panel provide feedback to the National Statistician. Finally, the papers are brought before the internal Population and Public Policy Design Authority Board to sign off the technical architecture and coherence with the wider Census objectives.

We have presented papers at MARP for: Variability Target for Response Rates in Collection, Census return rates RAG status methodology and Communal Establishment design. In developing the new methodology for Census return rates RAG (Red Amber Green) status, we consulted internally and externally with Stats Canada, Stats New Zealand, US Census Bureau and Australian Bureau of Statistics.

An update for how the three UK census offices are harmonising on the statistical procedures applied to the census data, such as methodologies for statistical disclosure control and estimation, was published in January 2021.

Statistical methods rehearsal

The 2020 Processing and Outputs Rehearsal demonstrated as far as possible that our workflow and interfaces with census could be implemented given the data available at the time of the rehearsal. Following on from this initial assurance, additional work will take place in early 2021 to test our 2021 statistical methods, including team workflows and governance procedures.

This will also provide further confidence that the methods that have been assured by MARP can be successfully implemented.

The Statistical Processing part of the system will continue to be developed and refined as early response data become available to tune the individual methods. This will provide the opportunity to further rehearse this part of the end-to-end system.


Our processing pipelines have been assured and approved by various internal groups and by MARP. The pipeline includes methods, extract points, linkage to alternative data and when differing form types are consolidated into a single pipeline. It is used by all teams involved in the end-to-end processing flow as a main point of reference for where their methods or services are used.

We collaborate with other producers, within the UK, to develop our statistics, overcome practical obstacles, and share best practice. The Data Processing Harmonisation working group manages relationships between 2021 Census Data Processing programmes of work across the UK, identifying potential areas of joint working and documenting synergies and differences in the way the data are processed.

Each UK census office will publish their methods, and where appropriate reference will be made to whether they differ from the other UK census offices, and if so the reasoning for this. The ONS intends to publish this information in 2022.

Census coverage survey

The census aims to capture the entire population, but even with a variety of strategies to maximise response (see Section 8: Achieving our quality targets and maximising response) it is inevitable that some people will not be counted (undercoverage), and some people are counted more than once or in the wrong location (overcoverage).

Coverage estimation processes measure the extent of undercoverage and overcoverage errors in the census data to be estimated. This allows us to provide population size estimates with higher accuracy than simply by using raw census counts. In the 2001 and 2011 Censuses of England and Wales, the coverage-adjusted population size estimates were the main published census outputs. The undercoverage and overcoverage errors vary substantially by demographic characteristics (such as age and sex) and geography. In the 2011 Census of England and Wales, we estimated there to be 6.0% undercoverage and 0.6% overcoverage.

To estimate these levels of undercoverage and overcoverage, we use an independent re-count known as the Census Coverage Survey (CCS). The CCS will start six weeks after census day and will consist of short face-to-face interviews on the doorstep. Every household in a random sample of unit postcodes will be asked a subset of census questions. The CCS interviewers identify all the households in the sampled postcodes and then interview them. They do not use the Census Address Frame. The sample is stratified by local authority and the hard-to-count index. The total sample size will be approximately 350,000 households.

CCS data will be linked to the corresponding census data where available, which allows us to identify undercoverage and overcoverage in those areas. From this, we create statistical models (principally via a process known as capture and recapture (YouTube) or dual system estimation (PDF, 817KB) to provide population size estimates for both sampled and non-sampled areas.

In 2011, the estimation approach was used to measure undercoverage and overcoverage independently for around 100 areas by the hard-to-count stratum. This was because of the paper processing schedule and the time taken to process.

For Census 2021, we will be using a modified version of the previous approach using a (mixed effects) logistic regression-based method that can be applied to larger areas. It will use information from across the whole of England and Wales at once, allowing a higher precision of estimates while still taking into account local differences. This means the estimates can be produced more quickly as there is just one (albeit more complex) model to fit and assess rather than 100 simpler models.

Confidence intervals are calculated at national and local authority level as part of the coverage estimation process. These are the confidence intervals that will be reported against the pre-defined quality criteria.

Census quality survey

A Census Quality Survey (CQS) has been run in each of the last two censuses to estimate the level of respondent error as an indicator of its quality. It aims to measure the accuracy of answers given to census questions by interviewing a sample of the census respondents and asking them the same questions asked in the census. By comparing the responses given in the CQS to those given in the census, agreement rates will be calculated, which will provide an indication of how accurately the census questionnaire has been completed by the general public.

The 2011 CQS was conducted through face-to-face interviews but because of the current pandemic, we will be using telephone interviews instead. We tested this approach in the pilot survey in early 2020. This should allow us to collect good quality data while minimising risk to the public or our staff.

The recommendation for conducting a Census Quality Survey in 2021 followed detailed investigation of the suitability of existing data sources for measuring respondent error in the census.

The Methodology Assurance Review Panel have agreed the telephone-based approach and the paper has been published.

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11. Outputs development

An update was provided on outputs in the Statistical design for Census 2021, England and Wales article published on 1 October 2020. This details the work undertaken following the 2018 consultation, Initial View on Census 2021 Output Content Design. The article also provides an update on our statistical disclosure control methods.

The Census 2021 outputs webinar held in December 2020 provided further insight into our progress, aims and dissemination plans for the suite of Census 2021 products, services and outputs. The aims of the webinar were to:

  • share the lessons learnt from the 2011 Census, the 2018 Output consultation and ongoing user research

  • outline the proposed suite of Census 2021 outputs, products and services

  • demonstrate how Census 2021 outputs and dissemination approaches will be flexible, timely and accessible

  • describe the methods for protecting confidentiality in outputs (statistical disclosure control)

  • consider how the ONS and census users can work together to assess the impact of the coronavirus pandemic on using census outputs

We have also updated our Census 2021 outputs pages on the ONS website. These describe our latest developments and plans for the ONS's suite of Census 2021 products, services and dissemination approaches.

We intend to hold a consultation in spring or summer 2021, which will outline our detailed plans for Census 2021 outputs, including proposed table specifications. Where appropriate, questions relating to UK data will be harmonised with Northern Irelands’ equivalent consultation. We are also planning to produce an outputs prospectus, which will be available in autumn or winter 2021. This will update the proposals made in the consultation based on user feedback, into a statement of what will be provided from the 2021 Census. It is also intended to include an indicative release schedule, and details of how users will be able to access the census outputs and analysis. A link to the consultation will be available from our Census Transformation Programmes consultations page and the ONS Engagement Hub once it is live.

Over 6,000 users have registered an interest in updates about the 2021 Census. They will be informed about the consultation using the census email alerts, alongside communication activities to ensure the widest range of audiences are aware (including those interested in particular communities or with specific interests). We will run a series of events around the consultation to explain and discuss what is being presented.

Census Analysis Programme

The Census Analysis Programme will aid understanding and interpretation of the census data needed by our diverse range of users and stakeholders. In addition, it will inform government policy and public debate. Our aim is to deliver new outputs and products, using innovative methods, and use all available sources to fill analysis gaps for our users.

We are currently developing a flexible analysis plan that will take account of:

  • important policy questions and user needs (identified through continuous engagement)

  • commitments made in the White Paper

  • new admin data sources developed through the population statistics transformation programme transformation activity

  • meeting the programme benefits (£5 billion)

  • corporate strategies and standards

  • UK level outputs

We engage with a wide range of users with a particular focus on how they use our data and their particular needs from future data. From this information we are able to tailor our analyses to meet these criteria and thereby ensure the production of relevant statistics that fit particular user needs. We aim to share analysis plans as part of the wider consultation in spring or summer 2021.

We are considering how we will quality assure our analysis. We have an awareness of data sources that may be of use in assessing the accuracy, reliability and comparability of Census 2021 data. The awareness of social and legislative changes is also significant. This information can be used to validate continuity or changes in trends displayed within Census 2021 data in comparison with previous censuses and surveys. We will also engage with external colleagues who can be of assistance in assessing the quality of data and statistics.

The Census Analysis Working Group ensures a collaborative and coherent approach to the production and dissemination of 2021 Census analysis and related outputs, in line with wider activity across the Census and Data Collection Transformation Programme (CDCTP). Specifically, it will:

  • agree and implement a stakeholder engagement plan to ensure that activities and messages are aligned

  • agree a flexible analysis plan that is responsive to stakeholder priorities and user needs

  • design and publish analysis outputs that aim to achieve public and policy impact


The ONS Census 2021 Output Geography Policy, products and services consultation ran between 5 November 2020 and18 December 2020. The consultation gave census users the opportunity to comment on our plans for the dissemination of census statistics and proposed census geography policy. This geography policy focuses largely on our plans for maintaining small area geographies: Output Areas, Lower layer Super Output Areas, and Middle layer Super Output Areas. We also set out our plans for producing geography products and services.

We intend to continue the use of Output Areas (OAs), and generally to build other areas as a best fit of Output Areas. As with previous censuses, we are looking to keep changes to OAs to under 5% and are recommending that we include some targeted OA re-alignment within that to make a better fit to ward and parish boundaries where there have been significant changes since 2003. We will update existing census-based geography products such as Travel to Work areas and Area Classifications.

Our response to the consultation will be published in spring 2021.

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12. Future developments

The Office for Statistics Regulation (OSR) will carry out the Phase 2 assessment using this report as evidence, as well as other documentation in the public domain. As part of the assessment, the OSR will:

  • continue to engage with census teams, to receive updates on progress of Census 2021

  • engage with users, to garner users and stakeholders' views and experiences of the 2021 Census for England and Wales

The OSR aim to publish their assessment in autumn 2021 on the UK Statistics Authority website. The assessment report will include any further requirements that we need to take forward and address. We aim to publish an update on how we have responded to the OSR requirements on our National Statistics Accreditation web page, to keep users notified of our progress.

This process confirms the England and Wales' Census 2021 National Statistics accreditation status and will be complete before the first census outputs are released in 2022.

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