Why the UK census should not be replaced with alternative sources of data

• Scholars have expressed concern that the government intends to scrap the census altogether, in favour of using other, administrative sources of population data.
• The issue is not whether administrative data can supplement census data – it undoubtedly can.
• They argue that using only alternative sources of information without the census to compare them against could ultimately lead to inaccuracies.

An unparalleled resource

• It is this ambition to collect data about the complete population that makes the census so unique, unparalleled by much smaller social surveys.
• The data collected in this way is crucial to understanding the changing social and demographic geographies of the UK.
• As well as the finances, there are also questions around the survey’s efficacy, when multiple organisations already gather citizen data as a matter of routine.

Alternative sources

• Most of the data is now collected and disseminated electronically rather than on paper.
• There are also ever more ways to freely explore and visualise the data.
• The ONS’s consultation document, entitled “The future of population and migration statistics in England and Wales”, suggests that various sources of administrative data can be linked and collated to create what is, in effect, a pseudo-census.

Potential for inaccuracy

• A lot of effort has been made by the ONS to explore what it terms “census alternatives” and to understand their potential advantages and disadvantages.
• Imagine, for example, that we used the national pupil database to estimate the ethnic composition of neighbourhoods.
• Generally, however, the more we zoom into such smaller data-sets, to explore neighbourhood-level patterns and differences, the more the possibility for inaccuracy increases.
• It provides a lot of geographically detailed data about people and places, but that information is updated infrequently.

• As a geographer, interested in detailed understandings of where people live, that is my preference.
• I agree with the signatories of the open letter that the government has not convincingly argued for scrapping the census.

Richard Harris had received funding from various organisations, including ESRC-UKRI, to develop research that uses census data.