Census Geography: Scotland 2001

For the 2001 census in Scotland, the lowest level "Output Areas" (OAs) were created using a method designed to maximise continuity with the OAs used in 1991. These were computer-generated and based on pre-existing digital boundaries for unit postcodes. The 32,604 Scottish OAs contain an average of 119 persons and 51 households, making them smaller than OAs in England and Wales. The minimum threshold for publication of census data was 100 persons and 40 households and no OAs were created to be smaller than this. Because no definitive boundaries exist for unit postcodes, these were automatically generated as part of the design process and the OA boundaries can therefore contain large "spikes" and other irregularities reflecting the computer-generated nature of the underlying postcode boundaries.

OAs nest within postcode sectors, which are the equivalent of the ward level in England. Scottish OAs are groups of unit postcodes that fit as well as possible to higher-level geographical areas. Postcode sectors vary widely in population size. They are variously described by a code which most closely matches their position in the postcode hierarchy (e.g. "PA4 4") or by a code within the census hierarchy (e.g. "60QDC24"). There are also electoral wards in Scotland but these do not nest exactly within the census geography hierarchy. The local government tier comprises Council Areas. The codes for these different levels are combined to create a 10-character alphanumeric code. There is no county level in the Scottish administrative geography and the characters 00 are used in this field which could contain a county code in England. Area names are applied to all levels about the OA. This census geography coding scheme will be found within postcode directories, census datasets and the Neighbourhood Statistics website.

A particular complexity with the 2001 census is that different population thresholds were set for different sets of statistical outputs. More detailed statistical tabulations known as the "standard tables" had thresholds of 1000 persons and 400 households and were intended to be available at the postcode sector level. As some wards are less than the required size, there are unfortunately different versions of postcode sectors in a few instances, with the result that the census area statistics (CAS) sectors and standard tables (ST) sectors with the same area code may not refer to exactly the same geographical area!

Digital boundary data are freely available for all units in the hierarchy.

Example