Current Government Statistical Service (GSS) Harmonisation team workplan

Current harmonised standard

The current harmonised standard for ethnicity is based on the questions used in UK censuses in 2011.

The recommendation is that people choose their own answer to the question about their ethnic group. This is because ethnicity will mean something different to each person.

It is also recommended that this standard is used together with the religion harmonised standard and national identity harmonised standard. The questions should be asked in the following order: national identity, ethnic group, religion.

For the censuses in England and Wales 2021 and Scotland in 2022, the current harmonised standard was reviewed and adapted. This was because of changes in respondent needs. The census questions were produced by balancing the new respondent needs with the need for coherence and comparability.

Because of this comprehensive work, if you are planning to include a new ethnicity question in your data collection and cannot wait for the review work to be completed, the questions in the censuses in England and Wales 2021 and Scotland in 2022 are recommended for data collection for ethnic groups at present. We recognise however, that user and respondent needs may have changed since the census questions were developed.

Progress since 2022

We began work to update the ethnic group harmonised standard following the publication of our initial workplan in 2022. Ethnicity was prioritised in 2022 due to:

• definitions, terminology, and thinking on the topic changing and developing
• events such as the Black Lives Matter movement and COVID-19 pandemic, which have demonstrated the need for more granular ethnic group data
• harmonisation’s response to the Inclusive Data Task Force’s recommendations to ensure the ethnicity standard reflects the diversity of the UK population

Ethnicity continues to be a focus for Harmonisation as an emerging priority of the future of population and migration statistics in England and Wales.

The broad aim of the work is to improve the inclusivity of the question for minority ethnic groups. We have now finished the research and early engagement work and published the findings from phase 1 and phase 2 of this discovery phase in 2023. These reports outline the issues discovered with the current question, as well as data user needs.

In June 2025 we published an overview of our redesign research to date, outlining our emerging approach to a more inclusive and flexible ethnicity harmonised standard. Informed by extensive engagement and testing across the UK, the proposed changes, such as multiselect functionality, aim to better reflect how people self-identify. We are committing to maintaining alignment with the five high-level census categories to support data comparability.

In September 2025, we published findings from a review of ‘write-in’ responses from a range of UK sources. This work built on the methods outlined in our December 2024 publication, ”additional work to explore potential new response options“. The research presented in these two publications shows how we are exploring user needs for expanded response options for the new standard. Findings from the write-in response review will be considered alongside evidence gathered through public consultation later in 2025.  

Priority activities

Priority activities for this next stage of work include:

• conducting an Autumn consultation to review the response options available and inform our final design
• testing possible improvements and changes to the question design
• considering how any proposed changes to the ethnicity questions will impact the national identity and religion harmonised standards – in terms of how they are used and ordered when collecting data on cultural identity

Timescale

The project timescales are guided by Agile and Respondent Centred Design methodologies, adopting a ‘gold’ approach to our question design. Progress updates about the work and any revised timescales will be published on this page in early 2025.

We are now working to design and test updates to the ethnicity standard.

We expect to finish our research in the following timescales:

• announcing the response options for the new standard – summer 2026
• online mode – late 2026
• paper mode – summer 2027

These standards will be published thereafter, pending relevant approval and sign-off.

Other data collection modes will be designed after this.

Current harmonised standard

To collect data on disability in line with the Equality Act (2010) for Great Britain or the Disability Discrimination Act (1995) for Northern Ireland, the current recommendation is to use both of these standards together:

• long-lasting health conditions and illness harmonised standard
• activity restriction harmonised standard

Users can also collect data using the impairment harmonised standard. This will give more information about the things that people self-report they can or cannot do. These questions were developed before the UK censuses in 2011.

Progress since 2022

Work to update the disability and impairment harmonised standards began following the publication of the initial workplan in 2022. Since then, the Harmonisation team have published findings from their research and early engagement work. These reviews outline the strengths and weaknesses of the current standard, user needs for disability data and areas for potential improvement of the existing standards.

The findings from phase 1 of the research were published in March 2023.

The findings from phase 2 of the research were published in June 2025.

Latest update

Following the published recommendation on the future of population and migration statistics, including the recommendation for an England and Wales census in 2031, work on the disability and impairment harmonised standards is paused.

This will give the Harmonisation team space to consider all the current harmonised standards, prioritise updates across each topic, and communicate proposed standards for Census 2031.

Timescale

Updates on the status of the disability and impairment standards, and the work being undertaken by the Harmonisation team in light of the Census 2031 recommendation will be provided through the workplan, as they become available.

Current harmonised standards and guidance

Gender Identity

Our previous ‘under development’ gender identity harmonised standard, published in July 2020, was created using research and testing undertaken for Census 2021 in England and Wales. It was published as ‘under development’, acknowledging the need for further research to develop the standard. However, there are limitations to the data collected from this question. As of 12 September 2024, the gender identity estimates from Census 2021 are no longer accredited official statistics and are classified as official statistics in development. The ONS requested this change in designation after patterns were identified in the Census data that suggested that some respondents may not have interpreted the Census 2021 gender identity question as intended, notably those with lower levels of English language proficiency. In November 2023 an ONS report on the quality of Census 2021 gender identity data noted this bias, and analysis of Scotland’s 2022 Census trans status and history data has added weight to this observation. More information can be found in the final report on the quality of Census 2021 gender identity data, and in the National Statistical blog about the strengths and limitations of gender identity statistics.

Therefore, we have archived our gender identity data harmonised standard while we work to develop new harmonised standards for sex and gender identity. We have replaced the archived standard with new guidance for producers of statistics and researchers (December 2024) who are currently using, or thinking about including, a gender identity question on their surveys or in their administrative data collection.

Sex

There is currently no harmonised standard on the topic of sex. Published harmonised standards include definitions, survey questions, suggested presentations, and information for data users. The GSS Harmonisation page on sex provides summary information for statistical producers on the way that sex has been collected in the UK’s censuses. However, these questions and associated respondent guidance were designed before the April 2025 UK Supreme Court judgment on the meaning of sex for the purposes of the Equalities Act 2010. This workplan sets out our intention to establish a harmonised standard for sex for future use. We have published an interim statement on our sex guidance page, setting out the priority work being done on this topic and when our published standard will be available. Guidance for collecting and reporting data about sex and gender identity in official statistics in line with the principles of the Code of Practice for Statistics has been published by the Office for Statistics Regulation.

Progress since 2024

In December 2024 we launched a new phase of work towards agreed harmonised standards for sex and gender identity data collection. Harmonised standards allow people to effectively and accurately compare data that has been collected across different datasets. The harmonised standards we develop will consider both the collection of primary research data, and the secondary use of administrative-based data for research purposes.

Throughout this workplan, we are using the term “user” to refer to producers of statistics and data users. We are using the term “respondents” to refer to people who will be answering data collection questions and providing data during survey-based data collection, administrative-based data collection, or during testing research to develop harmonised standards.

We will be user and respondent-led on this work, and we will use the findings from each phase of user engagement and question testing to directly inform our subsequent work. Updates on our work will be published regularly throughout the development cycle.

Both agile methodology and the Respondent-Centred Design Framework emphasise the importance of gathering user needs early in project delivery, and using these needs to inform all subsequent work you undertake. By developing harmonised standards iteratively based on the needs of our users and the feedback we gather from respondents, we can ensure that the final harmonised standards are effective, evidence-based, and fit for purpose. Agile delivery consists of three main phases prior to going live; these are Discovery, Alpha, and Beta.

Discovery Phase

The Discovery Phase is about gathering insights from users and respondents about their needs. User needs refer to the requirements of statistical producers and data users. Respondent needs include usability, acceptability, and question comprehension.

During our Discovery Phase to date we have engaged with cross-government data collectors and producers of official statistics, to understand their needs for new harmonised standards. We also held a series of listening events across the UK in Spring 2025 to hear from data users, statistical producers and members of the public interested in data and statistics. As sex and gender identity data collection is important internationally, we have also engaged with international colleagues from National Statistical Offices to learn from their approach to sex and gender identity data collection.

We undertook a review of UK surveys collecting data on sex, gender identity or both, primarily identified through the most recent equalities data audit. The focus of this audit was government surveys, however some surveys conducted by non-government organisations were included. We also conducted a scoping review of UK academic literature covering sex and gender identity data collection and statistics.

We are currently completing qualitative research with respondents to understand how individuals with a range of backgrounds and perspectives conceptualise the topics of sex and gender identity. This means learning about what they draw upon to reach their understanding of different terminology and concepts, the thought processes that take place when surveyed, and how different questionnaire response options are understood.

More information on our findings from this Discovery Phase can be found in our published report.

Alpha Phase

The Alpha phase is about using the insights gathered from Discovery research to make evidence-based decisions about question design. Question prototypes are designed, tested through research, refined based on research feedback, and then retested. This iterative improvement process continues until a final question design has been produced that is testing well and meets both users’ and respondents’ needs.

Our work with statistical producers and data users has found that there are clear priorities across the Government Statistical Service to be able to collect data aligned with the current legal positions, as set out in the Gender Recognition Act 2004 and the 2025 Supreme Court ruling on the definition of sex for the Equality Act 2010. We are now in the Alpha phase of our work towards a sex harmonised standard for these purposes.

Our workplan will continue to include research to explore user needs for, and respondents’ own interpretation of, terminology and questions on gender, trans status, and gender identity. Consequently, we anticipate a longer period of qualitative discovery work with users on these topics before progressing to Alpha. We will also continue to research other topics related to sex such as variations in sex characteristics (VSC, sometimes referred to as intersex, or differences of sex development) during this time.

In moving into Alpha phase for the sex harmonised standard, we will design and test questions and respondent guidance to understand how they perform in terms of clarity, respondent comprehension, acceptability, accessibility, and data quality and comparability. We will conduct testing research with a wide range of different UK populations to gather insights and respondent feedback about the questions we have developed. We will use these findings to iterate and improve the questions, until we have prototypes that are testing well qualitatively.

Beta Phase

The Beta phase is about quantitatively testing the questions that have been developed, at scale. This gathers statistical survey data insights and the ability to evaluate the effectiveness of the question design.

Our plans for this will be informed by work in previous phases. They will be developed as we learn more about the concepts in use and question iterations throughout the Alpha phase.

Priority activities

In May 2026, we published an update on developing sex and gender identity harmonised standards: findings from phase 1 of our research. The report summarises the first phase of discovery and engagement activities to update harmonised standards and guidance for the collection of sex and gender identity data.

The GSS Harmonisation team recognise the importance for statistical producers to be able to rely on evidence-based harmonised standards for data collection on sex. Most people will not need help to answer a question on their sex. For those that do, users of harmonised standards need to be sure that the questions and associated respondent guidance are suitable for the purposes for which they are collecting data. Official guidance and legislation for data collectors to consider when determining what their data needs on this topic are, include the:

• Equality Act 2010 (which legally protects people from discrimination in the workplace and in wider society based on sex, among other protected characteristics)
• Gender Recognition Act 2004 (which enables people to change their legally recognised sex by obtaining a Gender Recognition Certificate, or GRC)

In April 2025, the UK Supreme Court ruled that sex, for the purposes of the Equality Act, refers to biological sex unmodified by a GRC. This means that sex-based protections under the Equality Act 2010 must be based on biological sex, that is, the sex of a person at birth. We use the term “certificated sex” to mean a person’s sex at birth or as modified by a GRC.

To support statistical producers currently considering whether and how to make changes to data collection on sex, we are prioritising testing for a harmonised standard which supports data collection for:

1. Biological sex (sex at birth)
   and
2. Certificated sex (sex at birth or as modified by GRC)

This work has been accelerated, reflecting the urgent user need for statistical guidance shared with us by official statistics producers. We are currently undertaking cognitive and usability testing with participants of diverse backgrounds and characteristics to ensure that question wording and associated respondent guidance are easily understood and correctly interpreted. This testing ensures a rigorous evidence base for our new recommended standard, which we will publish in Summer 2026.

We will continue work to develop a new standard for gender identity, and we recognise that user needs and the context for official data collection on sex will continue to evolve. Our work with users, stakeholders and respondents will continue throughout our workplan, and our guidance on data collection on these topics may need to change further as circumstances change.

Timescales

We commenced respondent testing for sex data collection questions in Spring 2026.

We expect to carry out further discovery work exploring concepts of gender, trans status, and gender identity during 2026. We will commence respondent testing for gender identity questions following this work. We also expect to carry out further qualitative research and engagement with variations in sex characteristics (VSC, sometimes referred to as intersex, or differences of sex development) populations during this time.

Our prospective timelines for finishing qualitative research for the development of updated sex and gender identity harmonised standards are as follows:

• Summer 2026 – harmonised standard online self-completion mode for biological sex (sex at birth) and certificated sex (sex at birth or as modified by GRC) data collection, applicable for survey or administrative data collection
• Spring 2027 – harmonised standard online self-completion mode for gender identity data collection, applicable for survey or administrative data collection

These standards will be published thereafter, pending quantitative review, relevant approval and sign-off.

Standards for other data collection modes will be designed after this.

If you are interested in being kept informed of our progress, or would like to contribute to any of the phases of work previously described, please contact Outreach.Engagement.comms@ons.gov.uk.