Consultation Response: Future of Population Statistics

1. According to the National Statistician, Ian Diamond, ‘we have reached a point where a serious question can be asked about the role the census plays in our statistical system’. The consultation is clearly intended to lay the groundwork for abolishing the 2031 census, replacing it with an untested patchwork of administrative data and surveys.
2. An increased reliance on administrative data risks an increasingly fragmented and inaccurate data landscape. There is currently no mechanism for administrative data owners to be held accountable for the quality of their data. Data owners do not necessarily see their contribution to the national data infrastructure as a priority. Even with a variable as basic as sex, we have seen various administrative sources moving away from collecting accurate data, due to the pressure of internal or external lobbying (Sullivan, Murray and Mackenzie 2023). The consultation document characterizes administrative data as providing “full coverage” on sex. This is inaccurate, as the collection of data on sex has been eroded in recent years, and is no longer consistent. We note also that a lack of harmonization and accuracy in key variables causes problems with data linkage.
3. Administrative data is a vital supplement to the census, but the argument that it can replace all the functions of the census has not been convincingly made. There appears to be an element of wishful thinking in this view given the absence of a national identity system in the UK. Census data provides the sampling frame for survey data, and the standard against which representativeness is judged. It is vital in providing the benchmark for equalities monitoring. Administrative data cannot fulfil these functions of census data. Census completion, while not 100%, remains very high and has the advantage of being a legal requirement. Administrative data sources, to various degrees, will disproportionately omit hard-to-reach populations which are not registered with service providers and will additionally suffer from item non-response and non-consent to data-sharing, both of which may disproportionately affect particular population groups.
4. The ONS has a weak track record of user-engagement. Greater willingness to listen to expert opinion would have avoided undesirable outcomes in the case of the census sex question guidance (Sullivan 2021) and in the case of the gender identity data (Biggs 2023). There is little sign from the ONS that lessons have been learned from these mistakes. The consultation document mentions the Inclusive Data Taskforce. This taskforce has made eminently sensible recommendations regarding the collection of data on sex, but their findings do not appear to have been promoted to data providers by UKSA.
5. We call upon the Office for National Statistics to conduct the census in 2031. Any alternative using administrative data needs to be implemented and proven to yield comprehensive and accurate results—equivalent in quality to those yielded by the census—before any plan to abolish the decennial census.
6. We further call for UKSA to support efforts to improve the accuracy and harmonisation of administrative data, including, but not limited to, ensuring that sex is recorded as standard and not conflated with gender identity.

Signatories