Assessment of compliance with the Code of Practice for Statistics – 2021 Census in England and Wales

17 November 2021
Last updated:
25 July 2022

Executive Summary

Why this assessment is needed

The Census is one of the most important sources of data and statistics, informing decisions about almost every aspect of life within the UK. It allows users – including government, local authorities, academics, and commercial businesses – access to important information on the people and households of the UK and helps people get a better understanding of the places in which they live and work.

The Office for Statistics Regulation (OSR) is carrying out assessments of the UK Censuses produced by the Office for National Statistics (ONS), the National Records of Scotland (NRS) and the Northern Ireland Statistics and Research Agency (NISRA). The assessments will allow OSR to recommend whether the Census 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.

It is essential that the data and statistics from the Censuses are reliable and provide valuable insights, meeting the standards of trustworthiness, quality and value outlined in the Code of Practice for Statistics. This assessment report focuses on the 2021 Census in England and Wales, produced by ONS, and aims to identify areas of strength, good practice and innovation in ONS’s Census planning and development as well as identifying some areas where improvements need to be made.

This webpage was updated on 2 December 2021 to add a PDF downloadable version of the report.

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What we found

ONS has successfully delivered Census operations for England and Wales at a time of significant change and in unusual circumstances. The response to Census saw ONS exceed the return rate targets that it set for itself, both overall and for local authority areas; 97 percent of occupied households completed Census returns and all local authority areas saw over 90 percent occupied household return rates. It has worked hard to ensure the safety and wellbeing of its staff and the general public in doing so and these efforts should not be understated. The assessment team recognises the hard work and commitment of ONS to achieve this – from senior leaders, across the numerous specialist teams, and of course including those working in the field.

The data from Census 2021 will provide a unique snapshot of life in England and Wales, taken during the COVID-19 pandemic. Data collected during this time, on topics such as employment, travel, and household status, may well be unusual or changed from what might have been expected. ONS now has an important role in understanding the impacts on the data and seeking to address any unmet user needs as a result.

ONS should continue its work to ensure that Census outputs are accompanied by finalised information on quality to support users and assure them on the data sources and methods used in their preparation. This will be particularly important for 2021 Census data when it comes to areas of change – for example, on data particularly affected by COVID-19, for new Census questions, or where concerns from users have been raised such as on data collected on sex as, in response to a High Court order, ONS made a change to its online guidance during live operations. ONS has a responsibility to support and assure users of the quality of Census data and its plans to deliver this alongside Census outputs.

To enable enhanced quality assurance arrangements in Census data processing, ONS now aims to release its first Census outputs slightly later than originally planned, in late spring 2022, and all other estimates within 24 months of Census. ONS is developing new tools and reporting formats with the aim of providing users with more-flexible, timely access to data and delivering greater clarity and insight to support the use of Census data and statistics. Delivering high quality Census outputs at the earliest opportunity is vital to delivering public value from the Census.

ONS has recently completed a large-scale consultation exercise with data users and stakeholders on its plans for Census outputs. This is one of a range of different user engagement exercises which has been undertaken throughout ONS’s work on Census. ONS utilises various tools and approaches as part of its engagement to gather user views, get expert advice, update stakeholders of its plans, and explain its decision making – this includes formal consultations, user advisory groups, webinars and public events.

Having open and effective dialogue with users and stakeholders is vital in demonstrating that ONS is a trustworthy organisation that actively listens and responds to users’ views. We consider that, for some users, elements of ONS communications and engagement could have been handled better and confidence in ONS’s trustworthiness may have reduced; ONS’s communications linked to the Census sex question was an example of this. ONS needs to learn lessons from its experiences – both good and bad – for future Census user engagement and more broadly across the organisation.

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We have identified several ways ONS needs to implement improvements to support appropriate use of the data and meet users’ needs to comply with the highest standards of the Code.

ONS has made little information widely available on the steps it is taking to investigate, or otherwise meet, users’ needs for data affected by COVID-19. This is a significant gap in the assurances offered by ONS on its plans to address impacts on data.

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.

Further steps need to be taken by ONS to communicate its plans and provide more-detailed information, when available, to users of UK population estimates and UK Census data in particular.

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.

ONS made a change to its guidance for the Census sex question during live Census collection operations and while it told us that it expects this to have minimal impact on the Census data, ONS needs to publish suitable evidence to support this.

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.

To assure users of the value and quality of Census data, ONS should ensure its plans to provide information on quality – including information on data collection and processing, quality assurance activities and quality measures, methods and use of administrative data, and ONS’s judgement on appropriate use of Census data – are delivered as planned.

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.

With such a wide and varied set of users of Census data, ONS needs to engage with user groups with different requirements and interests. This includes from special interest groups or topic-focussed perspective or when, for example, considering the needs of users with different levels of expertise or accessibility requirements.

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.

Producing timely and accurate data from the Census is vital to ensuring high public value. We recognise the improvements to ONS’s quality assurance processes – and how this reflects ONS’s commitment to quality – although this has affected the release schedule for Census outputs.

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.

The current ONS Census webpages contain a wide range of materials, research, plans, and reports, focussed on providing information to aid with transparency throughout its planning and development stages although it is still difficult to find materials and navigate through the ONS Census webpages.

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.


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Judgement on National Statistics Status

We have identified seven requirements for ONS to address in order to ensure the high standards of public value, quality and trustworthiness associated with National Statistics designation are met.

Once ONS has demonstrated that the improvements covered by these requirements have been made or provided sufficient assurance that our expectation for the data and statistics will be met, OSR will recommend to the UK Statistics Authority that National Statistics status for these statistics be confirmed. ONS is aiming to meet the requirements of this report in the coming months so a designation decision can be made ahead of first Census outputs in late spring 2022.


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