Local census trans numbers should not be used, says official statistics body

The latest census should not be used to estimate the size of the trans population in local areas of England and Wales, the official statistics body has said.

The Office for National Statistics (ONS) has, for the first time, advised against using some figures published as part of the 2021 census regarding gender identity, after concerns some respondents had not understood what they were being asked.

The ONS first acknowledged in 2023 that there might have been some confusion among people answering the gender identity question, and last year confirmed a downgrading of the data amid concern some respondents may not have understood the question properly due to language barriers.

The statistics body said in September last year that it had requested that the estimates from the 2021 survey be reclassified from being official statistics to “official statistics in development”.

That census was the first time the voluntary question on gender identity was included in the wide-ranging survey, which takes place every 10 years.

The question asked “Is the gender you identify with the same as your sex registered at birth?”

It showed that 262,000 people in England and Wales, 0.5% of the population aged 16 and over, reported that their gender identity was different from their sex registered at birth.

In its first category, it said the 2021 estimates can be used to provide a “broad indication” of the overall size of the trans population in England and Wales.

However, in its second category, it said there is a “high level of uncertainty” if using the estimates to make geographical comparisons of the proportions of trans people between local authorities, regions, and at country level for England and Wales.

It also urged caution when estimating the proportion of the trans populations in different ethnicities and religious groups.

But in its strictest category, the ONS said the 2021 estimates “should not be used” to estimate the numbers of trans populations in local areas.

It added that these estimates should not be used to provide insights into the relationship between identifying as trans and having lower levels of English language proficiency or different qualification levels.

In a blog accompanying the update, ONS deputy national statistician Emma Rourke said while all census statistics have a level of uncertainty, “the potential misinterpretation of the gender identity question adds extra uncertainty”.

She wrote: “This is particularly impactful here as when looking at a small population, such as the trans population, a small percentage of inaccurate responses, can have a relatively large impact on the estimates of trans people.

“These uncertainties mean the estimates should not be used for detailed comparisons between local areas or for certain characteristics, nor should they be used as precise estimates of the trans population to support service delivery.”

The ONS said it is engaging in work across the UK “to build a robust and detailed understanding of user and respondent needs on the topics of sex and gender identity”, with findings to be published later this year.

They said next steps will include decisions about designing “prototype questions to be tested, refined based on feedback and tested again with a range of people”.