NEWS3 February 2021

Mapping with more: 20 years of geodemographics

Data analytics Innovations News Public Sector Trends UK

Geodemographics is becoming more detailed and using new sources of data. A Market Research Society webinar to celebrate 20 years of the Geodemographics Knowledge Base examined how the industry is evolving.


More granularity
Geodemographics has its roots in the 19th century poverty maps of Charles Booth, which depicted areas of social deprivation and wealth across the capital. It has come into its own as a discipline since the 1970s, when it began to be applied to marketing, advertising and survey research.

Despite the advances in technology since then, it is the changes to data classification, allowing more granularity, which have helped to transform geodemographics in the 21st century, said Barry Leventhal, who helped found the Census and Geodemographics Group (CGG) in 1989.

“The essence of geodemographics has not changed at all – the neighbourhood classification still looks the same, still segments small areas into types, still uses cluster analysis and creates a hierarchical segmentation of types,” said Leventhal. “But under the bonnet, much has changed in the way that classification is done and the data that goes into it.”

This has been seen, for example, in the granularity of the census data. According to Leventhal, output areas, the smallest geographical units available from the census, changed in size in 2001 from 180 households in each section and with no relation to postcodes to 125 households per area and aligned with existing postcodes.

Additional data has also been brought into the classifications – for example, postcode address file for the Land Registry and lifestyle surveys – all of which can help marketing and research. “Geodemographics became more highly targeted while keeping in it the neighbourhood backdrop image provided by the census,” says Leventhal.

The rise of open data
There are far more sources of open data that can be used alongside that from the traditional census, and computer processing power has enabled far quicker analysis. “This enabled smaller agencies to enter the marketplace with their own innovative products and solutions,” said Leventhal.

The Geodemographics Knowledge Base proposed in 1999 by Peter Furness at a CGG meeting has helped bring these multiple sources together in a single database. “Finding relevant information on the web – which was still in its infancy – was a pretty hit or miss process,” said Leventhal. “Peter suggested bringing together all of the links for all the useful websites on geodemographics and the census into a single portal.” Since then, the Geodemographics Knowledge Base has been expanded, including regular expert blogs.

Paul Longley, professor of geographic information science at University College London, said the amount of data now available could allow more extensive analysis of the history of the UK’s cities and shifts in population.

“There is no reason in principle why we can’t now produce temporarily harmonised data in geodemographics over a 50-year time horizon to look at the slow kaleidoscope of change that happened over the last century or so,” Longley said.

“Our ability to map things has improved tremendously. We have improved our abilities to map geodemographics,” he added. “Open data empowers every one of us to create our own bespoke area classifications.”

This has been augmented by the use of consumer data, said Longley, as well more niche data sources such as historical telephone directories. Then there is the rise of the internet. “The availability of individual level names and address as well as occupational data from the digital census project has allowed us to recreate the Booth maps,” Longley said.

The census
The 2021 census in England and Wales will take place mid-pandemic, with Scotland having decided to delay its census until 2022. Leventhal expressed concern, in response to an audience question, about how the data would be used without any UK-wide consensus.

“I am struggling to understand how the data is going to be used,” he said. “I can’t really justify their decision to go ahead, but they felt they had to.”

He added that the Office for National Statistics had set up a discussion forum to discuss the issue and see if there are any solutions to help make the data more usable UK-wide.

This year’s census could be the last in its current form. One idea being considered is using administrative data from the government to create an administrative data census. If this is done, the risk would be that the richness of traditional census data would be lost, and therefore threaten the efficacy of geodemographics, argued Leventhal. “We can be sure that geodemographics users are going to be awaiting this decision with great interest and taking part in the debate,” Leventhal said.

1 Comment

3 years ago

Liam: thank you for your post! Want to add to your point of richness that changes can be found in the geodemographic data. Been using ESRI Tapestry zip code look up maps for many years to assist our clients at RDS in understanding a visitors' beliefs, perspectives and expectations of an experience in order to deliver a more satisfying and truthful connections. I believe that demographics are much more than numbers but rather the why. Thanks!

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