Dear Ed,
Thank you for your engagement with our work on gender identity estimates for England and Wales from Census 2021. I am writing to you about the designation of these statistics.
Gender identity is a complex and important topic. The voluntary gender identity question on Census 2021 was the first of its kind. It has provided a unique opportunity to learn more about gender identity in England and Wales and the best approach to collecting high quality data on this topic. Publishing these data has provided new insights and prompted valuable discussion about the strengths and limitations of the estimates. We always seek to consider new evidence and information when it becomes available and to use this to improve the information we can provide to users of our estimates.
There is great value in the data that has been collected on gender identity. However, we also recognise that we can do more to support users with how to interpret the data and ensure the limitations are clear. To support this, ONS is planning to publish further explanation of the uncertainty associated with the estimates and guidance on their appropriate use. In addition, I would like to request that the gender identity estimates from Census 2021 are no longer accredited official statistics and are instead classified as official statistics in development. This will better reflect their innovative nature and the evolving understanding of gender identity.
As you know, following user feedback and the Office for Statistics Regulation’s (OSR’s) interim report in October 2023, the ONS published a quality review of the Census 2021 gender identity data in November 2023. The report summarised the work done to check the consistency of the results with the best comparable sources available at that time: NHS England’s GP Patient Survey, the Canadian 2021 Census and surveys in the United States.
We now also have data on trans status and history from the latest Census in Scotland. The trans population estimate for Scotland (0.44%) is broadly comparable to England (0.55%) and Wales (0.40%), representing around 1 in 200 people aged 16 and over. Some differences in estimates are expected, reflecting different questions, asked of different populations, at different points in time. However, these sources provide broadly consistent estimates at a national level.
Our focus is therefore making sure limitations are clear for users of sub-national or other smaller group breakdowns of the data. Reflecting issues raised by others, the ONS November 2023 report noted that some respondents may not have interpreted the question as intended, notably people with lower English language skills in some communities. The new evidence from Scotland’s Census adds greater weight to this statement. ONS cannot quantify all the uncertainty surrounding responses to the Census 2021 question on gender identity, however the available evidence does show there is potential for bias in how the question was answered by those who responded that they did not speak English well. Changing the designation of the statistics helps to signal the limitations arising from this issue, while also better signalling the fact that our knowledge and understanding of the best approach to collecting data on gender identity continues to evolve.
We are working with colleagues across the Government Statistical Service (GSS), including National Records Scotland, and other stakeholders to develop a harmonised standard for a future question and to share guidance on use and communication of outputs from existing survey questions.
I would be very happy to speak with you to discuss this further, and my teams will continue to work with your team as we seek to provide statistics that uphold the highest standards of trustworthiness, quality, and value.
I am copying this letter to Professor Sir Ian Diamond, National Statistician, Jon Wroth-Smith, Director of Census Statistics (National Records Scotland), Stephanie Howarth, Chief Statistician (Welsh Government) and the ONS Statistics Head of Profession Office.
Yours sincerely,
Emma Rourke Deputy National Statistician, Health, Population and Methods Group | Office for National Statistics