Dear Sir Ian,

Confirmation of National Statistics designation for 2021 Census in England and Wales

Tomorrow will see the publication of the first estimates of the population of England and Wales on Census Day 2021. This is a significant milestone and one which reflects the enormous efforts from all those who work on the Census 2021 in England and Wales.

I would like to thank the ONS teams involved in census on how they have responded to the requirements from Assessment Report 361: 2021 Census in England and Wales. It has been clear to me that ONS is dedicated to delivering data and statistics of high quality, which will meet the needs of a wide range of interested parties, researchers and decision makers – from government to individual members of the public – in line with the standards of the Code of Practice for Statistics. On behalf of the Board of the UK Statistics Authority, I am pleased to confirm the designation of National Statistics for outputs from the Census 2021 in England and Wales. We have included the detail around our judgement in the annex to this letter.

What was noticeable across the range of planning, development and delivery activities was ONS’s ambitious and innovative approach to Census 2021. ONS has implemented improvements to enhance the quality and value of the data for users in areas such as delivering a successful online-first approach to completing census questionnaires; introducing new quality assurance processes where local authorities could share their insights on provisional, anonymised census estimates; and the development of a new dissemination tool which will allow users to create their own bespoke data tables.

These census estimates will sit within the broader landscape of population data which will become available over the coming year, including mid-2021 and rebased population estimates, and research outputs from ONS’s administrative data-based population and migration transformation programme. I’m sure users will be very interested in these outputs and the insights they will bring. It will be important both to support users to navigate this landscape and also to facilitate the most appropriate use of these data.

I look forward to the release of these census estimates, the first of many releases planned for the coming years. My team will continue to engage with ONS and advise on compliance with the Code of Practice for Statistics compliance as required.

I am copying this letter to Pete Benton, Deputy National Statistician for Health, Population and Methods, ONS; Rachel Skentelbery, Deputy Head of Profession for Statistics, ONS; Stephanie Howarth, Chief Statistician, Welsh Government.

Yours sincerely

Ed Humpherson
Director General for Regulation

Annex: Review of actions taken in response to Assessment Report 361: Assessment of 2021 Census in England and Wales, run by the Office for National Statistics (ONS)

Requirement 1

In order to support society’s need for information, ONS needs to clearly communicate how 2021 Census data may be impacted by COVID-19 and how it plans to address any unmet user needs. ONS should ensure this information is communicated in an accessible and timely way, being open on plans, developments and progress even where definitive answers or solutions are still being sought.

Actions taken and commitments made by ONS to meet the requirement

  • In the run up to and during live census operations, ONS employed various strategies to adapt and seek to minimise how data might be affected by COVID-19, for example updating the question guidance to help respondents understand how questions should be answered in light of the pandemic. Details of ONS’s operational planning response to COVID-19 were published in October 2020 and, in April 2021, ONS also published information on the steps it took to ensure an accurate estimates of students.
  • ONS set up an internal taskforce to review COVID-19 impacts on census data and consider how any data gaps or unmet user needs might be met.
  • In its various communications, ONS continues to raise awareness with users on the possible impacts on census data, for example it released information on ‘Taking a census during a period of change’ which discussed potential changes to the data collected in its outputs consultation proposals document. References were also included in ONS’s update blogs and news articles, an example being this 28 January 2022 blog which mentions ONS’s work on understanding which areas of the census can offer insights into the pandemic and where new sources of data could be used to support outputs.
  • ONS has committed to publish a Quality and Methodology Information (QMI) report alongside its first Census 2021 outputs. The report will provide some insights for data on students and for some urban areas on how the pandemic resulted in changes to where people would normally be resident. In both cases ONS has used alternative data sources to better understand changes to the population since census data, for example Greater London Authority’s analysis of population change in London during the pandemic.
  • ONS has committed to provide further analysis to users on areas such as labour market and travel to work.

OSR’s evaluation of evidence

ONS has run a successful live census operation exercise in England and Wales, achieving high response rates while ensuring the safety of its field force and the general public. It has been transparent in communicating its plans and how it has adapted to running a census at that challenging time, offering reassurance to users, stakeholders and the public of its work.

ONS has continued to draw users’ attention to possible data limitations with running a census during a pandemic through a variety of different communication routes. While work continues to fully evaluate the impacts on the data, ONS has taken the opportunity to raise awareness and help support users in understanding what this might mean for census data.

ONS has committed to provide further analysis on COVID-19 alongside its future outputs.

Requirement 2

To assure users of how their data needs will be addressed, ONS needs to provide users with transparent, accessible and timely information on how it will provide UK population estimates for 2021 and UK Census data. ONS should continue to work with, and align communications with, NRS and NISRA to explain any impacts on data quality and describe where user needs may or may not be met as a result.

Actions taken and commitments made by ONS to meet the requirement

  • ONS has provided users with updates on its plans across its range of population statistics and produced a population statistics and sources guide, last updated in May 2022. This sets out guidance on the different sources of population estimates – including whether they are official estimates or research, and the main uses of these data – for Census 2021, mid-2021 and rebased population estimates, and the proof of concept for the demographic accounting system as well as others.
  • ONS has committed to providing comparisons of census estimates with other population estimates, such as the mid-year estimates and admin-based population estimates later in 2022. In addition, ONS has committed to provide comparisons alongside its topic analysis, for example on how labour market census estimates compare with data from the Labour Force Survey.
  • ONS has established and continues to engage with the UK data user group about data needs and priorities for UK census data. UK data needs were also explored in ONS’s output consultation.
  • ONS has updated and improved the information available on its UK Census data webpages. ONS continues to work closely with the National Records of Scotland (NRS) and the Northern Ireland Statistics and Research Agency (NISRA) to understand how the different censuses will be harmonised, or otherwise, and in the preparation of UK harmonisation materials to support use of these data.

OSR’s evaluation of evidence

ONS has taken a more coordinated approach in its recent communications on its plans for population outputs. This is well supported by its statistics and sources guide.

ONS has made clear commitments to undertake analyses comparing different sources which should further help support the most appropriate use of these data.

ONS has engaged with UK data users with the aim of providing the most appropriate UK estimates to serve their needs. Work on UK data has continued to be well co-ordinated across ONS, NISRA and NRS.

Requirement 3

ONS should be open and transparent in publishing its plans to evaluate and mitigate any risk to data given the change in the sex question guidance during live Census collection operations. ONS should provide appropriate assurances to users of the quality of these data and any implications for use should be clearly explained, including at disaggregated levels, alongside Census outputs.

Actions taken and commitments made by ONS to meet the requirement

  • ONS has reviewed its operational data to understand the impact of the change in guidance. It is reassured that the impact is minimal.
  • ONS has confirmed that its QMI report will share data with users on the number of sex question guidance views at different times during live operations and the number of response differences between household and separate individual returns.
  • ONS plans to to publish further analysis on the data quality of individual census questions, including on the sex question, later in 2022.

OSR’s evaluation of evidence

ONS has made a clear commitment to provide users with its judgement on the quality of data on the sex question given the change in guidance alongside the first census outputs, with further quality information to be published later in 2022.

ONS should continue to listen to any user feedback on the assurances it provides and explore further investigation into the data where appropriate, including at disaggregated levels.

Requirement 4

ONS should ensure finalised documentation on quality, information and judgements on suitable data sources, and methods and their application are complete. All supporting information should be sufficiently open and easily available to Census data users alongside its range of Census outputs.

Actions taken and commitments made by ONS to meet the requirement

  • ONS has been thorough and transparent with its plans on assuring quality and its development of methods. For example, using the Methodological Assurance Review panel – Census to gain assurance and advice on methodology. Minutes and papers from this panel are available on the UK Statistics Authority website.
  • ONS introduced a new quality assurance process with local authorities for Census 2021. While this may have impacted on the timeliness of access to first census results, it has offered greater quality assurance of census estimates at local authority level.
  • Throughout data processing, ONS has discussed any issues and findings with the other census offices so all were sighted and could learn from the types of investigations they carried out.
  • ONS has reviewed the quality documentation from the 2011 Census to determine what quality information it will replicate for 2021. From this, ONS has developed an internal quality assurance prospectus for the quality products and content it needs to produce.
  • Information on quality will be made available through a landing page on the census web pages, signposting users to all relevant quality and methodology documentation.
  • ONS’s QMI report will describe high-level quality characteristics and strengths and limitations of the data. More detailed reporting, for example ONS’s Census Quality Survey Report or topic-based quality reports, will be published later in 2022.

OSR’s evaluation of evidence

Based on the materials provided to OSR and conversations with ONS, we continue to be assured by the thorough quality assurance processes being undertaken.

ONS is considering the accessibility of quality and methods information for users, and we are comfortable with ONS’s plans to provide this alongside its census outputs.

Requirement 5

In order to ensure the relevance of data and statistics to users, ONS needs to continue to develop and enhance its user engagement activities, connecting with a broad range of users and embracing challenge. ONS should continually review and seek to implement improvements in its engagement strategies and should ensure its decision making is open and transparent, explaining where users’ needs can or cannot be met.

Actions taken and commitments made by ONS to meet the requirement

  • ONS uses a variety of communication and engagement tools to inform, promote, and gain feedback from users and stakeholders. For example, during its outputs consultation (July to October 2021), ONS engaged with users and stakeholders through webinars and ran a ‘show and tell’ event ahead of publication of the first response to the outputs consultation.
  • ONS bolstered engagement with local authorities on the new quality assurance process timelines, following feedback about concerns raised to OSR. ONS addressed this in its newsletter to LAs on 17 December 2021.

Other examples of continued ONS engagement include:

  • ONS was involved in a webinar hosted by the Market Research Society Census and GeoDems Group on the Future of Census in February 2022.
  • ONS continues its external engagement exercise around its Census 2021 schools campaign “Let’s Count
  • ONS’s media campaign in the run up to first census outputs has built on previous engagement and helped increase awareness for the public, data users, and key stakeholders ahead of this first release.
  • ONS has committed to deliver further webinars and other engagement exercises to showcase the census results, for example to support the publication of Census 2021 topic summaries which should be published between October and the end of 2022.

OSR’s evaluation of evidence

ONS has continued to engage with the public, census data users, and key stakeholders over the past months. Broadly speaking, ONS has been open and responsive within its engagement strategies, and if issues on communication have been raised with them, they have sought to make improvements.

ONS is in a strong position to strengthen and build on its user network. This will support it in delivering a successful communication campaign throughout the coming publication period.

Requirement 6

ONS needs to continue its efforts to deliver timely, accessible and flexible Census outputs – while ensuring sufficient data quality and supporting appropriate use of the data – mitigating any risks to further delay to the release of Census data and statistics. It should clearly communicate its plans and timelines for outputs at the earliest opportunity, updating and revising these as soon as more detail is available or to reflect any changes to its plans.

Actions taken and commitments made by ONS to meet the requirement

  • ONS’s output plans were shaped by users’ needs identified through its outputs consultation, which ran between July and October 2021. ONS published the outcomes of the consultation in two parts – part 1 and part 2. The consultation is informing ONS’s finalised release schedule and product specification.
  • On 1 March 2022, ONS informed users that the first census outputs would be postponed until early Summer 2022 due to delays in the local authority quality assurance processes. It also shared this update via mailing lists. A separate statement was also sent to local authorities to inform them of the delay.
  • On 24 May, ONS announced the date for the first release of Census 2021 estimates. ONS outlined its proposed outputs and release plans on its centralised Census 2021 outputs webpages which will be updated as details and timings become finalised.

OSR’s evaluation of evidence

Through the planning and developing of Census 2021 outputs, ONS has been transparent on its emerging thinking and has demonstrated that this has been driven by user needs.

ONS has introduced new local authority quality assurance processes. When ONS announced changes in its original timeframes for the release of first census outputs, this was provided with clear information on the reasons for the delay to users.

We are content that ONS will provide users with accessible information on its release plans via the census outputs webpages as they are finalised.

Requirement 7

To best support Census data users, ONS needs to continue to improve its webpage navigation for current materials. ONS’s plans for a separate website or webpages for Census outputs themselves will require sufficient consideration of its navigation and accessibility. ONS should keep webpages and content refreshed and current.

Actions taken and commitments made by ONS to meet the requirement

  • ONS has continued its efforts to improve website navigation including improved signposting across topics/webpages to aid with the accessibility of current information.
  • ONS ran a Web Estate Review between January and March 2022 which sought user feedback on their experiences of the current ONS web estate and what they need, and would like, in the future.
  • On 2 February 2022, ONS reached out to the UK data user working group to collate feedback on the UK census data webpages. It has subsequently made improvements and bolstered the information available for these users.

OSR’s evaluation of evidence

ONS continues to seek views and make improvements for its users, both for census and across its overall website. This can be challenging given the wealth of information across the range of census releases and required supporting information. However, ONS is committed to making Census 2021 data and statistics as accessible as possible.