Annex 2: Actions that ONS has taken in response to the Phase 2 Assessment requirements

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 in 2022:

In preparation for and during the live census operations, ONS adopted various strategies to adapt and seek to minimise how data might be affected by the pandemic, for example updating question guidance to help respondents understand how questions should be answered in light of the pandemic. 

ONS set up an internal task force to review the impact of the pandemic on census data and consider how any gaps or unmet user needs might be met. 

ONS committed to raising awareness with users on the possible impact of the pandemic on the census data. 

Actions taken by ONS since 2022:

ONS published a quality and methodology information (QMI) report alongside its first Census 2021 outputs which included a ‘conducting a census during the coronavirus pandemic’ section. This section states that the pandemic may have affected the data in different ways, that statistics will reflect circumstances in March 2021, and that for some students and in some urban areas there is evidence that the pandemic resulted in changes to where people lived (which may be temporary for some and permanent for others). Within the QMI, ONS also provides links to analysis carried out by others, for example the Greater London Authority’s analysis of population changes in London during the pandemic. 

ONS also published further analysis on specific areas impacted by the pandemic, such as travel to work and labour market variables. 

In its Quarterly update on population and migration statistics: May 2025, ONS has publicly committed to publishing a research paper on the impact of the coronavirus (COVID-19) pandemic, following on from Census 2021 in autumn 2025. 

OSR’s evaluation of evidence

ONS has considered the impact of the pandemic on census responses and how some topics may be affected more than others and communicated this in quality documentation. However, ONS has not fully evaluated the overall impact of the pandemic on census data or communicated the potential impact to users. This is particularly relevant for the onward use of the data when projecting forwards. More-explicit guidance is needed for users to fully support any decision making based on affected statistics.  

This requirement is partially met. As set out in Requirement 1 of this report, ONS should be more explicit in its guidance to support users in using data impacted by the pandemic, signpost users to relevant topic statistics to support a more holistic view and be transparent about the issues caused by the pandemic and explain which estimates may be impacted and why.  

We will continue to engage with ONS and review its planned publications on the impact of the pandemic later this year. 

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 in 2022:

ONS committed to providing users with comparisons of census estimates with other population estimates and topic analysis. 

ONS also committed to keeping users informed about its plans for delivering UK census outputs and continuing to work with NISRA and NRS to deliver UK-level outputs. There is a commitment from the three UK census offices, in the statement of agreement, to produce consistent, coherent and accessible statistics for the UK from Census 2021/2022. 

Actions taken by ONS since 2022:

On ONS’s UK census data webpage, last updated in February 2024, ONS states that the publication of UK Census 2021 and 2022 outputs is dependent on the availability of Scotland’s Census 2022 data and that it is still considering the approach for UK census outputs. 

More recently, ONS published ‘Combining and comparing census figures across the UK’, to update users on its plans for UK-level outputs. 

Regarding comparisons of census estimates with other population estimates, in February 2023 ONS published ‘Transforming population statistics, comparing 2021 population estimates in England and Wales’, which compares census-based and admin-based population estimates and evaluates their quality. 

OSR’s evaluation of evidence

ONS committed to providing users with UK census outputs as part of phase two of the census delivery plan. However, these outputs have not yet been delivered.  

ONS updated users with its plans for UK census outputs. However, no timelines for publication have been set out. Some users told us that they would like to see UK-level outputs pointing to an unmet need.  

This requirement has been partially met. As set out in Recommendation 6, ONS should continue to keep users updated on its plans for publishing UK-level census estimates. 

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 in 2022:

ONS confirmed that its QMI report will share data with users on the number of views of the sex question guidance at different times during live operations and the number of response differences between household and separate individual returns. 

ONS committed to publishing further analysis on the data quality of individual census questions, including on the sex question, later in 2022. 

Actions taken by ONS since 2022:

Within the QMI, ONS published information about the sex question guidance, including the number of views before and after the change to the guidance and the percentage of responses received during these times. Where someone submitted a separate individual form as well as being included on their household form, ONS explains that there were fewer than 100 instances where sex responses differed between a form submitted before the guidance change and a duplicate for the same person after the guidance change. ONS does not know if these differences are linked to the guidance change, and it is not possible to know the effect of the guidance change for people who only submitted one response. 

ONS published the Census Quality Survey for Census 2021 in England and Wales in March 2023. This publication provides information about how many people gave the same answer to the Census Quality Survey and to the census, providing an indication of respondent error. ONS states that the highest agreement rate overall in 2021 was for sex, at 99.3%.  

OSR’s evaluation of evidence

ONS has investigated and evaluated any potential risk to data following the change in the sex question guidance and published its findings to support user confidence in the census data.  

This requirement has been met. 

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 in 2022:

ONS has been thorough and transparent with its quality assurance the census data. ONS has sought advice from experts both internal and external to ONS, including using the Methodological Assurance Review Panel (MARP) and sharing issues and findings with the other census offices to facilitate shared learning. 

ONS carried out a new quality assurance process, seeking insight from local authorities. While this may have impacted on the timeliness of access to first census results, it has offered greater quality assurance of census estimates at the local authority level. 

Actions taken by ONS since 2022:

To support user understanding and the use of the census estimates, ONS published a wide range of quality documentation, including detailed information on the Census Quality Survey (CQS) and topic-based quality reports. 

ONS’s quality and methodology report provided users with high-level quality information, including the strengths and limitations of the data.   

OSR’s evaluation of evidence

ONS has completed a thorough quality assurance process and published a broad range of documentation on quality, data sources and methods. However, there was not enough information for users on how to use the data in the context of the pandemic. 

ONS has not published its census general report, but it has told us that it plans to publish it soon. 

Some users we spoke to told us that whilst the documentation covered the relevant material, it was difficult to navigate, particularly for new users, and not well integrated into the data visualisation tools.  

Most of our expectations for this requirement have been met. In line with Recommendation 4, we expect ONS to review its census website to consider how it can enhance the navigation of the census quality information. 

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 in 2022:

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 publishing 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 local authorities on 17 December 2021. 

Actions taken by ONS since 2022:

ONS used social media channels during the output release phases to support public engagement and communication.  

OSR’s evaluation of evidence

ONS carried out extensive user engagement activities, for example, hosting information and instructional webinars and attending conferences with key stakeholders in attendance. ONS placed a key focus on promoting the digital products, primarily the create a custom dataset tool but also the census maps tool. 

ONS carried out extensive and effective user engagement through a range of channels, both in developing the census and delivering the outputs. It went to great lengths to reach users it wouldn’t normally engage with. 

Overall, most users were happy with ONS’s engagement and told us they were happy with the way that ONS responded to any individual requests. 

ONS did not effectively engage with some users, particularly users who provided more challenging feedback for ONS. This is particularly true for some local authorities who provided feedback as part of the quality assurance exercise. 

Most of our expectations for this requirement have been met. In line with Recommendation 5, ONS should be more open to scrutiny from key stakeholders and respond to feedback appropriately, detailing any actions taken and explaining why feedback was not acted on. 

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 in 2022:

ONS’s output plans were shaped by user needs identified through its outputs consultation, which ran between July and October 2021. 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.  

 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.  

Actions taken by ONS since 2022:

The 2021 England and Wales outputs were released in three phases, as outlined in ONS’s published ONS’s release plans. The ONS census website and release calendar are used to keep users up to date with published and upcoming publications.  

The ONS Census webpage is the central navigation page available for users to access 2021 Census statistics and data. A range of outputs, including in accessible formats, are available, including statistical bulletins, data tables, the flexible table builder and other data visualisation tools such as the census mapping tool. NOMIS is also available for users to obtain more-detailed granular breakdowns. ONS responds to users who make any ad hoc requests. 

OSR’s evaluation of evidence

ONS delivered the 2021 England and Wales Census outputs in a timely and orderly way in response to user views gathered from its consultation. ONS communicated its release plans publicly to manage user expectations.  

ONS demonstrated its flexibility through its publication of a range of outputs, including in accessible formats, covering a wide range of topics to meet user needs.  

Users spoke very highly of ONS’s create a custom dataset tool and interactive data visualisation tools. ONS’s development of the tools demonstrates a commitment to maximise the public value of census data through the functionality allowing users to create custom datasets in a way that meets individual needs.   

We are satisfied that where there were delays to individual publications, ONS communicated this to users. However, some users told us that they did not feel that ONS communicated the delays of publications very well and that publications were rescheduled at short notice.  

This requirement has been met.  In line with Recommendation 1, ONS should consider what action it can take to improve its communication of changes in future work. 

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 in 2022:

ONS 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 users’ 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. 

Actions taken by ONS since 2022: 

ONS told us that it is committed to making Census 2021 data and statistics as accessible as possible and has continued to improve website navigation throughout the publication of Census 2021 outputs by making improvements to signposting across topics/webpages. 

ONS published a specific subsection of the ONS website as a landing page for census outputs. This page provides users with links to a range of census publications, including the release calendar, the data visualisation tools and outputs from specific topic areas. It also provides users with links to external publications, including the Scotland census website and NOMIS, where users can access the data. These pages were kept up to date during the publication of the outputs. 

OSR’s evaluation of evidence  

We recognise that ONS has made some improvements to its website. The ONS census webpage brought together most of the information users need to maximise their understanding and use of the census outputs.  

However, more could have been done to optimise the navigation of census outputs for users and better integrate supporting quality documentation. This should be improved in line with user feedback. 

Most of our expectations for this requirement have been met. In line with Recommendation 4 on quality documentation and user feedback, we would like to see ONS continue to review website navigation.