Geodemographic Output Area Classifications for London, 2001-2011

UCL DEPARTMENT OF GEOGRAPHY

Geodemographic Output Area Classifications for London, 2001-2011

UCL Department of Geography, Gower Street, London, WC1E 6BT

Chris Gale* Paul Longleymapblog.in paul-longley.com@geogale

* Conference attendance kindly supported by RGS-IBG funded QMRG bursary


• Geodemographic Classifications• The 2001 Output Area Classification• London and the 2001 Output Area Classification• Change since 2001• Uncertainty and the 2001 Output Area Classification• Summary

Outline


Geodemographic Classifications• A Geodemographic Classification:

– Simplifies a large and complex body of information about a population, where and how they live and work.

– Based on premise that similar people live in similar locations, undertake similar activities and have similar lifestyles and that such area types will be distributed in different locations across a geographical space

• Clustering algorithms partition demographic data into groups sharing similar characteristics

• Commercial (MOSAIC, ACORN) and free (OAC) classifications available


The 2001 Output Area Classification (OAC)• Groups the UK population

into:– 7 Supergroups– 21 Groups– 52 Subgroups

• Only data source used is the 2001 Census– 41 Variables

• Variety of organisations use it including local government and commercial companies


OAC Cluster Distributions - UK and LondonSupergroup OAC - UK OAC - London

Blue Collar Communities 16.1% (35837) 2.5% (606)

City Living 7.5% (16637) 21.4% (5174)

Countryside 12.4% (27681) 0.1% (21)

Prospering Suburbs 21.2% (47250) 7.4% (1782)

Constrained by Circumstances 14.9% (33165) 2.5% (592)

Typical Traits 18.3% (40769) 10.1% (2430)

Multicultural 9.7% (21721) 56.1% (13535)

Counts in brackets


OAC Cluster Distributions - UK and London


2001 London Output Area Classification• Same methodology as the 2001 OAC• Uses same Census variables as the 2001 OAC - but

includes only data for London• 24,140 OAs cover London - instead of the 223,060 OAs

that cover the UK• London contains 9.24% of UK’s OAs and 12.5% of UK’s

population• 7 Supergroups created – Groups and Subgroups levels

were not clustered• Based on Petersen et.al. 2010 paper


2001 LOAC Cluster Distributions

Supergroup OA Count OA Percentage (%)

Suburban 2506 10.4

Council Flats 3678 15.2

Asian Quarters 2716 11.3

Central District 3409 14.1

Blue Collar 3114 12.9

City Commuter 3542 14.7

London Terraces 5175 21.4


2001 OAC vs. 2001 LOAC Cluster Profiles• 2001 LOACs clusters significantly different to those of

the 2001 OAC– Difference meant using same cluster names and profiles as

OAC was not possible for LOAC• Cluster names and profiles for 2001 LOAC created by

Petersen et.al.• Illustrates different results can be created by a regional

classification compared to a national alternative• 2001 LOAC better representation of London compared

to the 2001 OAC - but lacks compatibility and comparability with rest of the UK


Bespoke Geodemographic Classifications• Being able to easily create bespoke classifications

without any expert knowledge is one possible solution to unsatisfactory cluster assignment

• Using tools like ‘GeodemCreator’ classifications could have (but not limited to):– The variables modified– The geography changed– Different standardisation techniques and clustering

algorithms used• In the case of the 2001 OAC this could resolve a

problem when used at a regional level (e.g. London)


• Change happens across the UK – but this change happens at different rates for different areas

• The 2001 OAC uses Census data that is now 11 years old

• How much uncertainty in the 2001 OAC since 2001?• This uncertainty will vary depending on the amount of

change that has occurred in a particular area over time• A measure can be calculated to indicate how reliable

the 2001 OAC becomes over time

Change and OAC Uncertainty


• Uses Mid-Year Population Estimates from 2002 to 2010 at Output Area level

• Assumption:– The greater the population change from 2001 the greater

the uncertainty• Allows for the uncertainty of different OAC

Supergroups to be compared over time• Different methods can be used to visualise this

uncertainty

Uncertainty in London: 2001 OAC Case Study


• Current lack of data at Output Area level makes creating a more comprehensive measure of uncertainty difficult

• Assumes the greater the population change the more uncertain the classification – BUT population change could also be reaffirming OAC Supergroup allocation

• Should be used as more of a note of caution when using the 2001 OAC rather than a definite answer to if the classification is now ‘wrong’

• The uncertainty of the uncertainty measure needs to be taken into account

Uncertainty in London: 2001 OAC Case Study


• The 2001 OAC does not classify London well• The 2001 LOAC was created by Petersen et.al is one

solution to this • A measure of uncertainty gives some understanding

how reliable geodemographic classifications (that do not employ updating of variables) become over time

• The uncertainty measures themselves have a level of uncertainty

• Uncertainty measure does not quantify how much the OAC Supergroup assignment is ‘wrong’– BUT does allow for areas of possible change to be identified

Summary


Any Questions?

Chris Galemapblog.in

areaclassification.org.uk@geogale

[email protected]

Geodemographic Output Area Classifications for London, 2001-2011

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