Sex and gender harmonisation guidance

Policy details

Metadata item Details
Publication date:4 September 2019
Author:Callum Allison
Approver:Catherine Davies
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

In October 2020, the National Statistician established the Inclusive Data Taskforce to improve the UK’s inclusive data holdings in a broad range of areas, including the nine protected characteristics of the Equality Act. In September 2021, the Taskforce recommendations were published, some of which specifically refer to harmonised standards. The National Statistician’s response to these recommendations references the publication of a GSS Harmonisation Plan and the review, refinement and updating of harmonised standards. Further information on this work will be made available in due course.




Review frequency:

This page will be reviewed annually.


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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