It’s vital that census data is accurate

THE main purpose of the census is to provide robust data that governments need to develop policies, run public services and allocate funding.

Furthermore, public bodies use the census numbers to fulfil their duty under the Equalities Act 2010 to monitor and assess the impact of their policies in relation to sex.

As the only data source that provides full coverage of the population, the census allows analysis at a level of detail that sample surveys cannot, and it is paramount that it is accurate.

NHS funding is distributed to different services on the basis of need within population groups, taking into account age and sex, and medical research uses census data to calculate and understand variation in the incidence and prevalence of diseases across different populations. Knowing how many people live in an area and their characteristics allows local authorities to identify what communities need. For example, which areas need resources for maternity services.

Within the field of criminal justice, census data is used to monitor how offending and victimisation rates differ between men and women.

This can be used to develop policies on tackling crimes such as domestic violence.

The census also provides information on educational attainment by sex. In London, for example, they use this data for schools planning, and to identity gaps in youth service provision.

Sex, together with age, is a core topic frequently compared with other population characteristics and this data has been gathered since the very first census in 1801.

Because of the importance of the census, whatever decision is taken in 2021 is likely to set a precedent for other data collection exercises.

If the UK census authorities proceed with a sex question on a self-identification basis, we are likely to see other public bodies do the same.