The ONS Super Output Area (SOA) geography was designed specifically for statistical purposes and was first used to report on the 2001 Census. The geography is a hierarchical geography built up from a basic building block called and output area, five of which form a Lower Super Output Area (LSOA) and where five LSOA’s form a Middle Upper Output Area (MOSA).
On average LSOAs have an average population of 1,500 and MSOAs have 7,500 across England. There are nearly 33,000 LSOAs across England. The key feature about the SOA geography is that their boundaries rarely change which means they are useful if you want to monitor data over time. In fact the SOA boundaries in the county have only been changed once for the 2011 Census which increased the number of LSOAs in the county from 320 to 324, while the MSOA boundaries remained the same.
The main drawback of the SOA geography has been that they do not have meaningful names, rather a set of codes making them difficult to identify without looking at a map. Following the 2001 Census we adapted these boundaries to include a ‘local’ name to help identify their location within the county. This was done for both LSOAs and MSOAs and these names can be found in the maps and report pages within this site.
Further information on the ONS Census geography is available here: https://www.ons.gov.uk/methodology/geography/ukgeographies/censusgeography