This briefing examines the guidance proposed by UK census authorities to accompany the sex question. We argue that the UK is currently at risk of losing meaningful data on a key demographic variable used by policy-makers and statisticians, and recommend that the guidance is removed. The full briefing can be accessed here:
The three UK census authorities are proposing guidance to accompany the sex question in the 2021 census which instructs respondents to answer based on their self-declared gender identity. The main rationale they offer for this is that similar guidance was introduced in the 2011 census. However, this guidance was introduced without parliamentary or external scrutiny, or any assessment of the potential impact on data quality. A senior official in the National Records of Scotland recently admitted that it was not known if or how the 2011 guidance affected data reliability. Given the 2021 census is a ‘digital first’ census, it is likely that the guidance will be more prominent and, amongst particular sub-populations, the extent to which respondents will select their ‘sex’ based on their self-declared gender identity is unknown.
We recommend that the proposed guidance instructing respondents to answer the sex question based on their self-declared gender identity is removed. If needed, any guidance should simply provide a clear explanation of why data on sex is collected and emphasise the confidentiality of its handling, but decline to interpret the question further.