Public bodies should collect distinct data on both sex and gender identity to ensure accuracy and clarity of nationally held data, concludes a UK Government-commissioned report led by a UCL academic.

In February 2024, Professor Alice Sullivan (UCL Social Research Institute) was asked by the Department for Science, Innovation and Technology (DSIT) to conduct an independent review into the collection of accurate data and statistics on biological sex.

Published by DSIT, the “Review of data, statistics and research on sex and gender” report provides a timeline of how survey data has been collected since the 1960s and shows how the word “gender” started to replace sex in some data collection in the 1990s. In some survey data, gender was defined as sex; in others, gender was defined as identity.

Further, the review finds that from around 2015, the word gender started to be understood in terms of gender identity (the gender with which people identify, which can be different from the gender they were born into) and not binary sex, meaning robust and accurate data on biological sex was lost from some government and public body survey data.

In summary, the independent report advocates the importance of collecting high-quality data on biological sex to enable both good research and for effective policymaking across fields, including health and social care, crime and justice, education and the economy.

The report also highlights the need to distinguish between biological sex and gender identity in data collection. This is to ensure there is optimum understanding of differences between the sexes and differences according to gender identity, including transgender and non-binary identities, and to ensure full awareness of any disparities within and between all these groups.

Lead author, Professor Alice Sullivan, Head of Research at UCL Social Research Institute said, “Rather than removing data on sex, government and other data owners should collect data on both sex and transgender and gender-diverse identities. This will help develop a better understanding of the influence of both factors and the intersection between them, and this is crucial for research and policy-making.”

For the report, the team conducted a comprehensive review of policies, guidance, datasets and statistics, including administrative data, major flagship surveys, independent academic studies, clinical trials, polling data, and marketing exercises, and held over 30 stakeholder interviews with diverse government and public sector organizations.

In addition, they invited public submissions on UK data collection related to sex and/or gender identity which they perceived as inadequate or flawed and commissioned a legal opinion to ensure compliance with legal frameworks, such as GDPR and the European Commission on Human Rights (ECHR) Article 8 rights.

In summary, the report finds that conflating sex and gender identity in data collection hinders accurate statistical analysis and the ability to track outcomes of distinct groups.

It calls for the use of respectful data collection practices, which adhere to established principles of question design, clear communication about the purpose and benefits of data collection, and emphasizes the importance of political impartiality of data owners, that is, government and public sector organizations.

DSIT has shared the report and its recommendations with government departments for consideration.

The review was led by Professor Sullivan and assisted by independent policy analysts Murray Blackburn Mackenzie and Dr. Kathryn Webb at the University of Oxford.