The Office for National Statistics “hugely overestimated” the number of transgender people in the UK, Whitehall sources have claimed, as the body admitted it could have carried out “additional probing” before releasing the controversial data.
An official inquiry by the Office for Statistics Regulation (OSR) into the census finding that 260,000 people identified as transgender has drawn up several “lessons learned” from the way the data was handled by the ONS.
They include a conclusion the ONS should do more to communicate “uncertainty” about the data and should have sought external “quality assurance”.
The inquiry’s findings are likely to exacerbate tensions between ministers and the ONS after the body admitted earlier this month it had underestimated the size of the economy by nearly 2 per cent as of the end of 2021 – meaning Britain recovered to its pre-pandemic level almost two years ago.
A Whitehall source suggested the ONS executive, led by Prof Sir Ian Diamond, may have lost its “credibility” to accurately record sex and gender, based on its handling of the trans issue together with its separate loss of a legal challenge over the wording of the 2021 census.
The source said it was now clear the 2021 figures on gender, released in January, “hugely overestimated” the number of transgender people – a view they said was shared by multiple ministers.
Inquiry into findings
The inquiry into the findings was sparked after academics warned the wording of the census question, “is the gender you identify with the same as your sex registered at birth?” may have skewed the answers for respondents whose first language is not English, or who are less familiar with the language of gender identity.
Earlier this year, academics found those who speak English poorly were five times more likely to be transgender.
Michael Biggs, a professor of sociology at the University of Oxford, claimed that confusion over the question may explain why the London boroughs of Newham and Brent, which have a significant percentage of residents who speak English as a second language, recorded the highest proportion of transgender people in the UK.
Ed Humpherson, the head of the OSR, has written to the ONS setting out its initial observations.
His letter said the ONS team that carried out the “quality assurance” of the data “agreed that, with more time to look at all combinations of variables, for example looking at gender identity and ethnicity, it may have identified areas for additional probing and analysis.”
He added: “When releasing big data sets for the first time, it is inevitable users will want to interrogate and analyse the data for their own purposes.
“ONS could have done more to see this as an opportunity to crowdsource quality assurance, or at a minimum, be clearer that it was open to feedback as part of releasing the data.”
Mr Humpherson also said that “the communication of uncertainty should be strengthened”.
ONS stands by data
The ONS stood by its data, insisting: “The census estimates on gender identity remain the best available. They are broadly consistent with NHS data collected in the same year and other countries’ comparable data.
“The new, voluntary question went through rigorous development and testing involving trans and non-trans people and, through the census rehearsal, people who did not have English as their main language, before being finalised through legislation.
“We await the OSR interim findings and will publish further updates in due course.”
A spokesman for the OSR said: “Our review is ongoing, and we would not comment on speculation about its findings.”