Sex and gender harmonisation guidance

This harmonised standard is under development.

Following the Inclusive Data Taskforce recommendations, we plan to review and update the current harmonised standard. This is in line with the GSS Harmonisation Workplan.

You can find more information about this in the ‘Further information’ section of this page. If you would like to be involved with this work, please contact us at

Policy details

Metadata item Details
Publication date:4 September 2019
Author:GSS Harmonisation Team
Who this is for:Users and producers of statistics
Type:Harmonisation standards and guidance

What is harmonisation?

Harmonisation is the process of making statistics and data more comparable, consistent and coherent.

What is covered on this page?

This page provides information on work underway across the Government Statistical Service (GSS) to harmonise measures of sex and gender in data collection across government. We recognise that sex and gender are distinct concepts but as they are closely related, they are presented together on this page.

For more information or advice, please contact

Measuring sex in the UK censuses

The Office for National Statistics (ONS, who carry out the census in England and Wales), National Records of Scotland (NRS) and the Northern Ireland Statistics and Research Agency (NISRA) have been working closely together throughout development of the 2021 and 2022 Census questionnaires to share research and work towards harmonisation where possible. The GSS Harmonisation Team works across the UK to promote and facilitate harmonisation.

The sex data collected in the UK censuses is of importance, as much other data analysis is adjusted to match the proportions of the sexes found in the census. This is important data for understanding population dynamics and projecting future change.

The data gathered on sex in the three censuses will be harmonised across the UK. Information about the questions is provided below:

  • The 2011, 2021 (England, Wales and Northern Ireland) and 2022 (Scotland) sex questions ask: “What is your sex?”, with the response options “Female” and “Male”. This question on sex has been asked on the censuses for many decades and the consistency of this is unchanged, which is vital for identifying trends over time.
  • ONS, NRS and NISRA have engaged widely on the 2021 and 2022 censuses and thoroughly tested their proposals to ensure high quality and consistent data.

Related work

A number of related strands of work are underway across the UK, and some information on key projects is provided below. The teams working on all these projects are communicating regularly with one another to share research and coordinate where possible.

UK census gender identity question development

Census questions are being developed by the ONS and NRS to measure gender identity/trans status. NISRA do not currently plan to ask a question on this topic, however they have included a gender identity question in their Continuous Household Survey. The national statistics agencies and GSS Harmonisation Team have been liaising to share research and explore harmonisation of this data.

For England and Wales, further information can be found in the ONS question development reports.

Scottish Government working group on sex, gender and data

The Scottish Government have established a working group on sex, gender and data. Its membership comprises professionals from across statistical services and is led by the Chief Statistician. The group considers the guidance that should be offered to public bodies on the collection of data on sex and gender, including what form of data collection and disaggregation is most appropriate in different circumstances.

NHS England Unified Information Standard for Protected Characteristics Scoping Project

NHS England are currently carrying out an equality monitoring scoping project to assess the need for a unified information standard for the nine characteristics protected under the Equalities Act (2010). These include sex, gender reassignment, and sexual orientation. The ONS is a member of the Steering Group for the project and aims to ensure that the approach being developed takes account of developments across government.

Further information

Inclusive Data Taskforce and GSS Harmonisation Workplan

In October 2020, the National Statistician established the Inclusive Data Taskforce. It was designed to improve the UK’s inclusive data holdings in a broad range of areas. This includes the nine protected characteristics of the Equality Act.

In September 2021 the Taskforce recommendations were published. Some of these recommendations specifically refer to harmonisation.

In response to the recommendations, the Office for National Statistics (ONS) oversaw the publication of an Implementation Plan in January 2022. This gives information about the current and planned initiatives across the UK statistical system. It refers to a GSS Harmonisation workplan, which was published in February 2022. This workplan includes reviewing, refining, and updating harmonised standards.

The workplan sets out activities related to the topics of sex and gender identity. These include:

  • working with a range of stakeholders and user groups to understand and review user needs – this will use and add to the census research that has already been done
  • understanding what people need from a harmonised standard for sex, for both questions and guidance
  • monitoring and reviewing how the gender identity standard is working
  • changing the gender identity standard from ‘under development’ to ‘final’
  • publishing more guidance to help people use the question – for example, more information will be needed to explain how the gender identity question and sex question interact
  • testing possible improvements and changes to question design as needed

Timescales for this work will be guided by the feedback the team gets throughout the project. We are now working to:

  • publish a review of the gender identity standard and an updated standard with further guidance in summer 2022
  • run research and engagement activities throughout 2022
  • publish the first findings from our research and engagement in autumn 2022
  • publish a timetable for future work in autumn 2022 – this will include activities like designing, testing, and publishing additional guidance

If you would like to be involved with this work, please contact us at




Date Changes
26 June 2020 Minor updates have been made to reflect the progress of work in this area.
16 July 2020 Link to the gender identity data harmonised standard included.
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