Warwickshire Observatory - Statistical Geography

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Statistical Geography - Super Output Areas

Super Output Areas (SOAs) are a new geography that were introduced in 2004 and are replacing electoral wards as the primary means of the dissemination of small area statistics (N.B. Eletoral Wards are still a key component of the administrative geography, but their use for statistical purposes is being reduced by the introduction of SOAs).

SOAs are replacing electoral wards for statistical purposes for a number of reasons;

Electoral wards are subject to regular boundary reviews, making it difficult to develop trend based data
Electoral wards vary enormously in size across England and Wales (e.g. some wards may contain 30,000 residents whilst others may only contain 100 residents), this makes it near impossible to draw accurate comparisons across the country at an electoral ward level.

SOAs are designed to be consistent in size thus allowing comparisons to be more meaningfully made. It is also envisaged that the boundaries will not change, allowing trend based analysis for particular areas (e.g. specific area based initiatives such as regeneration schemes) to be developed. The underlying 'building block' for SOAs are Census Output Areas.

Due to disclosure control (i.e. the protection of anonymity, including even the perceived disclosure of personal information that may allow individuals to be identified) certain datasets can be released for smaller areas than others. 3 different SOA layers have been created;

Lower Layer: Each lower layer SOA contains between 1000-2000 people. They are much smaller than electoral wards (e.g. Camp Hill ward contains 5 lower level SOAs) but are constrained by electoral ward boundaries. A number of datasets are available at this level, including the IMD 2004, unemployment data and certain Census 2001 data. There are 333 lower layer SOAs in Warwickshire.

An example of how the lower layer SOAs within Camp Hill ward, Nuneaton nest within the electoral ward can be seen here.

Basic maps of lower layer Super Output Areas by district can be viewed below:

North Warwickshire
Nuneaton & Bedworth
Rugby
Stratford on Avon
Warwick

Middle layer: Middle Layer SOAs are built up from lower layer SOAs and contain approximately 7200 people. Middle layer SOAs are constrained to local authority boundaries (the 5 districts in Warwickshire) but not automatically to electoral wards.

Upper Layer: The exact nature of the upper layer SOAs is yet to be decided, although it is thought that the minimum number of people they will contain will be about 25,000.