Gender identity data harmonised standard

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:16 July 2020
Owner:GSS Harmonisation Team
Who this is for:Users and producers of statistics
Type:Harmonisation standards and guidance

What we mean by harmonisation

Harmonisation is the process of making statistics and data more comparable, consistent and coherent. This harmonised standard sets out how to collect and report statistics to ensure comparability across different data collections in the Government Statistical Service (GSS). This produces more useful statistics that give users a greater level of understanding.

Who this standard is for

This standard is for researchers who are considering including a question about gender identity on their surveys or within their administrative data collection.

This new harmonised standard will be useful to those in government departments and the wider public sector who are considering how best to collect data on gender identity.

Why we collect gender identity information

Data are needed for policy development, service planning and provision.

There is also a growing need for respondents to be able to record an identity, other than male or female, on surveys or forms.

At the moment, there is little official data on the topic of gender identity. The research done by the Office for National Statistics (ONS), Exploring existing data on gender identity and sexual orientation, found that few surveys currently collect gender identity data, specifically information about those whose gender identity is different from their sex registered at birth. For those that do, it is a relatively new topic, so available statistics or data are limited.

To date there has been no agreed best practice for collecting gender identity data. Collecting gender identity data in a consistent manner will assist in building the evidence base. This would help to bring an awareness of the size of the population whose gender identity is different from their sex registered at birth, their needs and access of specific services, and inequalities they may be facing.

Questions and response options (input)

To meet stakeholder needs, the proposed gender identity data harmonised standard (under development) been designed to collect two pieces of information:

  1. Whether a person’s gender identity is the same or different from their sex registered at birth – captured via the ‘Yes’ or ‘No’ response options.
  2. How people wish to self-describe their gender identity – captured via the free-text box.

This standard is about gender identity. It does not collect information on sex. Further information on the collection of data relating to sex can be found on the sex and gender harmonisation guidance webpage.

English language self-complete question

Question: Is the gender you identify with the same as your sex registered at birth? Response options:

  • Yes
  • No, enter gender identity
  • Prefer not to say

Welsh language self-complete question

Question: Ydy’r rhywedd rydych chi’n uniaethu ag ef yr un peth â’r rhyw a gofrestrwyd pan gawsoch chi eich geni?

Response options:

  • Ydy
  • Nac ydy, nodwch eich hunaniaeth o ran rhywedd
  • Mae’n well gen i beidio â dweud

Using this standard

Age of the respondent

This question has been developed for respondents aged 16 and over.

Free-text option

The inclusion of the free-text option is important as it increases acceptability of the question for members of the trans community, leading to them being more willing to answer the question. Further tick-box options have not been included because there are a variety of identities with which people may identify and the language related to this topic is developing.

However, detailed information should only be collected if there is a need for it. Therefore, we encourage consideration of how free-text information collected by the free-text option would be used before implementing the question.

If you do choose to use the gender identity harmonised standard without the free-text option, please email and share your experiences.

The “Prefer not to say” response option and refusals

Most surveys and administrative collections of data are voluntary, and it is good practice to advise individuals at the start of the data collection that they do not need to answer anything they do not want to answer. This means respondents should be able to skip this question if they do not wish to answer it.

Due to this question being sensitive for some respondents and the need to maintain privacy, we recommend that a way of not having to answer the question is explicitly provided; this is the ‘Prefer not to say’ option on the standard. This is in addition to the implicit option of refusing to answer the question. This is consistent with good practice in data collection for sensitive topics.

Question placement

We anticipate that a gender identity question may be asked with a question on sex as some data collectors may want to collect data on the protected characteristic of sex, female or male, in addition to data on gender identity.

The gender identity question and a sex question can be placed next to each other or apart. If the respondent cannot see that a gender identity question will follow it is recommended that a guidance note be added to the sex question to say that a gender identity question will follow.

Suitable data collection methods for this standard

The question has been developed primarily for self-completion on paper and online.

Guidance for data collection

How and where people will answer the questions

Privacy is an important issue in answering a question about gender identity, which is considered a personal matter.

If asking the question in a face-to-face context, aim to ensure respondents’ answers cannot be seen by others. For example, if the question is to be asked as part of a interviewer-led household survey, respondents could be offered the chance to complete the gender identity question themselves, thus enabling privacy from the household and interviewer.

Proxy response – completing the question on behalf of someone else

As is good data collection practice, a response from the individual themselves should be obtained wherever possible and we would recommend this for the collection of gender identity information.

Due to the sensitive and private nature of the topic, careful consideration should be given before enabling proxy response. We advise putting in place appropriate ways to maintain privacy and protect respondent confidentiality.

The ONS found that gender identity information can be collected by proxy if required but this may affect the quality of data collected.

However, the testing of proxy response was in relation to Census 2021 for England and Wales. In this case, individuals will be able to respond independently from the household questionnaire, with the individual response overriding household response. The ONS has not tested acceptability of proxy response in the context of general surveys and administrative data collections, which may differ.

The Northern Ireland Research and Statistics Agency (NISRA) currently ask a gender identity question in some of their household surveys, but it should be noted that proxy responses to the question are not permitted.

Presenting and reporting the data (outputs)

Recommended data presentation

In the table [data] represents where data should be inserted.

Gender identity the same as sex registered at birth [data]
Gender identity different from sex registered at birth [data]
Prefer not to say [data]
Spontaneous only: refusal or did not answer [data]

The following displays what responses we would expect to be categorised into the above data presentation template:

Gender identity the same as sex registered at birth – refers to those who selected ‘Yes’ and includes male when registered male at birth and female when registered female at birth.

Gender identity different from sex registered at birth – refers to those who selected ‘No’ and whose gender identity is not the same as the sex they were registered at birth. This is inclusive of a range of gender identities, including binary male or female genders when not the same as registered at birth, non-binary genders such as those on a continuum between male and female, and non-gendered identities (neither male nor female).

Prefer not to say – refers to those who responded with ‘Prefer not to say’.

Spontaneous only: refusal or did not answer – refers to those who have either refused to answer or more generally, where a response has not been given. This should not be presented as an option to the respondent, but it can be recorded. This is useful to infer the acceptability and usability of the question and will be beneficial to evaluating the standard while it is under development.


We aim to harmonise data collection and outputs across the United Kingdom (UK) where this is appropriate, however needs and circumstances sometimes differ between the countries.

We encourage researchers to implement the harmonised standard for collecting gender identity data.  If researchers implement this question in a UK-wide context they should bear in mind that data collected may not be fully comparable with country-specific official statistics.

Data collection across the UK

England and Wales

Census 2021 for England and Wales

The ONS is responsible for the census in England and Wales. Census 2021 in England and Wales will include a gender identity question. The Census (England) Regulations 2020 and Census (Wales) Regulations 2020 both came into force in June 2020. The development of the question has been informed by research and testing. It has been found to meet user needs identified for England and Wales. The question is available in both English and Welsh.

As this harmonised standard is based on the gender identity question for Census 2021 for England and Wales, data collected will be broadly comparable.

Crime Survey for England and Wales

The Crime Survey for England and Wales, conducted by Kantar on behalf of the ONS, has been trialling a gender identity question in a self-completion module on the questionnaire, as part of the face-to-face interviews. The question is based on that used in the 2019 Rehearsal for England and Wales for Census 2021, with the addition of ‘Prefer not to say’ and ‘Do not wish to answer’ response options.


Census 2022 for Scotland

The National Records of Scotland (NRS) are responsible for the census in Scotland. The Census (Scotland) Regulations 2020 came into force in June 2020. Scotland’s Census 2022 will include a question about trans status. Their testing showed this question was acceptable in Scotland and produced good quality data.

Information on this testing is available in the NRS Sex and Gender Identity Topic Report.

Northern Ireland

Census 2021 in Northern Ireland

The Northern Ireland Research and Statistics Agency (NISRA) are responsible for the census in Northern Ireland. NISRA do not plan to ask a question on gender identity in their Census 2021.

Household surveys

NISRA currently ask a gender identity question on some of their household surveys, which include:

The GSS Harmonisation Team will work closely with ONS, the Welsh Government, NRS and NISRA as part of the ongoing development process for the harmonised standard, and also to provide comparable Census 2021 outputs where possible.

Development of this standard

We have developed a question to collect data on those whose gender identity is different from their sex registered at birth. This question was developed as a priority. This harmonised standard uses the comprehensive research and testing that was done for Census 2021 in England and Wales.

This is the first gender identity data collection standard to be shared. It should be used primarily in online and paper self-completion contexts. This standard is still under development.

We are aware that further questions and guidance may be needed for specific situations.

You can find more information about our work in the ‘Further information’ section of this guidance.

Further information

ONS work related to gender identity

Further information about the ONS work in relation to gender identity, including research and testing, and work to develop a question for Census 2021, can be found on the gender identity webpage and in the report Sex and gender identity question development for Census 2021.

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

Contact details

You can contact the Gender Identity and Sexual Orientation Team at the Office for National Statistics (ONS) by emailing You can find more information about the ONS work on this topic on the ONS website.

You can contact the Government Statistical Service (GSS) Harmonisation Team by emailing

Review frequency:

This standard is under development. We will monitor its use and provide updated guidance in due course.


Date Changes
22 April 2021 The wording of the Welsh gender identity question was updated slightly to match the agreed wording for the Census paper questionnaire.
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