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The University of Southampton
Geography and Environmental Science

Redrawing the Lines

Geography experts from the University of Southampton have played a critical role in creating and managing small geographical areas for the publication of data from the 2001 and 2011 censuses for England and Wales and the Neighbourhood Statistics Service.

Research challenge

Before 2001, the Office for National Statistics (ONS) used the same geographic areas both to collect Census data and publish the results. These areas were created manually and had diverse population sizes and geographical shapes. In 1991, around 4,000 of these areas contained populations that were too small to meet confidentiality requirements and could therefore not be used to publish census data.

Changes to boundaries between censuses and wide variations in population sizes meant comparisons between areas were hindered. These issues highlight the need for controlled, standardised areas so that more accurate and detailed information is available on which to base analysis and planning.


The UK Census has been carried out every 10 years and provides a unique series of snapshots in time. It is a rich source of information about households and neighbourhoods.

The University of Southampton has a long history of collaborating with the ONS on the accuracy and statistical confidentiality of data.

Our solution

Research by Southampton geography academics – Professor David Martin, Dr Samantha Cockings and Andrew Harfoot - led to the means of creating an entirely new system of standardised areas that were fit for purpose, having standardised sizes and shapes and meeting a range of other criteria demanded by users. They developed automated zone design software that was used by ONS to create a new system of small Output Areas (OAs) for the 2001 Census. These were further developed into Super Output Areas (SOAs) to aggregate and publish a range of local data from other government administrative sources. For the 2011 census, the Southampton approach was applied again, resulting in updated Output Areas, most of which could be directly compared to those used in 2001.

This was the first time that the majority of output area boundaries didn’t change between censuses, greatly improving the analysis of local area data and revealing a unique view of how the population had changed through a 10-year period.

The Southampton team also contributed to another first by creating an entirely new set of areas called Workplace Zones that were specifically designed to publish Census workplace statistics. Before 2011 the same output areas were used to publish data about residents as well as workers and workplaces.

What was the impact?

These new geographical areas have formed the basis for an enormous range of decision-making and planning over the decade, including allocating resources to local areas and preparing for national emergencies.

The Southampton researchers have continued to work closely with ONS and have presented evidence to various influential committees, including the House of Commons Inquiries concerning the future of the Census itself.

David has participated in several ONS advisory boards including the UK Census Design and Methodology Committee, the Output Area Review Panel and the 2011 Census Quality Assurance Panel.

The software at the heart of this work is also being used in 10 countries around the world including Australia and New Zealand.

It is also available online to support wider work on official statistics, geographical aggregation problems and applied areas such as public health.

Redrawing the lines

Related Staff Member

Related Staff Member

Related Staff Member

The University of Southampton has a long history of collaborating with the ONS on the accuracy and statistical confidentiality of data.

David Martin - Professor of Geography

Communities and Local Government (2010) The English Indices of Deprivation 2010 - Technical Report  

Grady, S. C. and Enander, H. (2009) Geographic analysis of low birthweight and infant mortality in Michigan using automated zoning methodology International Journal of Health Geographics 8, 10  

House of Commons Treasury Committee (2008) Counting the Population Volume 1 HC-183 1 London:  

Neighbourhood Statistics Service  

Office for National Statistics (2004) Census 2001 Review and Evaluation. Census Geography: Evaluation Report  

Office for National Statistics (2012) Modification of Output Areas  

Output Area Classification User Group

Key Publications

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