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About the Area Classifications

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Frequently asked questions about the 2011 Area Classifications.

What is the coverage of the classifications?

Area Classifications have been produced for Great Britain following the 1971, 1981  and 1991 Census, and produced for the UK following the 2001 and 2011 Census.

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What geographic levels are available?

2001 Area Classifications are available at local authority district, health area, ward, Super Output Area/Data Zones, and Output Area level.

The 2011 Area Classifications at present just cover Output Areas and local authority districts, but updated  area classifications for other geographies are planned for later in 2015.

The 2001 Area Classifications reflect 2001 Census geographies, whilst the 2011 Area Classifications reflect 2011 Census geographies.

The classification for each geography is separate. The codes and names for each area classification apply to that classification only.

Where possible we have used different names with the classifications to minimise confusion, but this may not always be possible.

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How were the classifications produced?

Different statistical techniques were used, as appropriate, for each level of the classifications.

To find out more about the methods used in each classification please see the relevant methodology information.

Information is also available on the variables used in each classification.

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How is the information displayed?

With the 2011 Area Classifications the clusters are split into five main census dimensions: demographic, household composition, housing, socio-economic, and employment. For the 2001 Area Classifications a sixth grouping of ‘industry’ was also used.

Graphs characterising these areas are available at three levels of hierarchy: Supergroups, Groups Subgroups.

An example of a Supergroup with the 2011 Area Classification for Local Authorities is 'Coast and Heritage'; within this Supergroup there are two Groups: 'Coastal Resorts and Services’ and ‘Heritage Centres’ and within the first Group there are two Subgroups: ‘Resorts and Ports’ and ‘Coastal and Rural’.

Various supporting material is available to support the area classification codes and names assigned for different geographies, this includes cluster summaries, maps, methodology guidance, pen portraits and radial plots. 


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How are similar local authority districts shown?

To measure similarity between authorities, the squared euclidean distance (SED) has been used, which is based solely on the 59 variables used in the main classification.

In this context, the range is defined as the range between the two most similar authorities and the two most dissimilar authorities.

Pairs of local authorities are considered to be:

  • extremely similar if they have an SED of less than 1% of the range between the two most similar authorities and the two most dissimilar authorities

  • very similar if they have an SED of less than 2.5% per cent of the range

  • similar if they have an SED of less than 5% of the range

  • somewhat similar if they have an SED of less than 10% of the range

  • not similar if they are more than 10% of the total range

The ‘Corresponding local authorities’ (473.5 Kb Excel sheet) file is provided to show, individually, which are the most similar authorities.


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Amendments to the area classifications

With the 2011 Area Classification for Output Areas, an error was found in the labelling of two census variables (numbered 32 and 33 in the supporting documentation) used in helping to define two Subgroups. As a result two Subgroups have now been renamed:

4a1 is now Social Renting Young Families (previously Private Renting Young Families)

4a2 is now Private Renting New Arrivals (previously Social Renting New Arrivals)

All supporting material was updated on 15 April 2015 to reflect these changes.

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Content from the Office for National Statistics.
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