Making sense of the census

Census form - large 30 March 2011

Who are we? Where do we come from? The modern census is not limited to a head count, but also asks about our identity, how we live, what we do and what we believe in. Since 1801 there has been a census every ten years, providing a wealth of valuable data - not only for policymakers, but also for social scientists. This year’s census adds a new large batch of data to analyse, with the first results expected to appear in July 2012.

In the 1980s web-based technologies and new software radically increased the options for searching in census data. The ESRC/JISC Census Programme was set up in 1991, providing researchers with online access to census data from the 1971 census onwards. Later integration of the Samples of Anonymised Records, Scottish Longitudinal Study and Northern Ireland Longitudinal Study have increased the UK-wide range of data resources, while the Census.ac.uk website launched in 2007 made it easier to access the resources.

Accessing data over 142,000 times

The number of researchers registering to use the ESRC census service is an indicator of just how sought-after the census datasets have become.

"At the end of the 2009-10 service year there were 23,093 people in universities registered to use the ESRC service. They logged on and accessed census datasets 142,486 times," says Professor David Martin, Programme Co-ordinator for the ESRC Census of Population Programme. These numbers do not include researchers who get support to access secure data from the UK Census Longitudinal Studies, or the repeated use and analysis of downloaded datasets.

While politicians use census data to plan policies on for instance housing, education and public services, social scientists can find datasets to underpin a wide range of research. Anything from trends in employment, migration and the composition of communities to household size, relationships and ethnicity can be mined from UK censuses, making it a popular resource for researchers.

Area data most popular

Figures from the ESRC Census Programme show that census data for geographical areas are by far the most popular. "The enormous majority of accesses are for area-based aggregate data and for boundary data and other geographical products", adds Professor Martin. The smaller numbers of downloads for census microdata (anonymised sample records for individual people and households) reflects the fact that these are usually downloaded only once, and then analysed repeatedly for detailed data.

The programme's 2010 user survey shows that the service was used most for geographic research, with 20 per cent of users from this discipline, followed by economics and econometrics (15 per cent) and sociology (5.9 per cent).

Web access - transforming census research

Easy web access has changed the landscape, emphasises Professor Martin. "What we have now is a complete transformation of what existed ten years ago. We are also looking at exciting new developments in the dissemination of 2011 census data - including new interfaces allowing users to specify their own queries and data extractions in much more flexible ways that has been possible until now."

There are still many things we don't know about the people of Britain, but making sense of the census is becoming ever easier.