Census Geography: Wales 1981

The 1981 census geography of Wales shares a common structure with that used in England. The lowest level of geography was the "Enumeration District" (ED). The 6,700 EDs were designed by staff at the Office of Population Censuses and Surveys (OPCS) who drew boundaries by hand onto large scale Ordnance Survey maps, intended to demarcate the area to be covered by each census enumerator. EDs were drawn so as to nest neatly within wards. Guidance notes indicated the approximate numbers of addresses to be included in EDs in different types of neighbourhood with the intention of equalizing enumerators' workloads as far as possible. This resulted in generally larger ED populations in easy to enumerate urban and suburban areas, and smaller populations in rural EDs and some hard to enumerate urban areas. The overall mean is 426 persons and 158 households. Because no exact up to date information was available to the ED planners, there are many instances of EDs whose eventual census populations fell below the census publication thresholds of 25 persons and 8 households, and these EDs were "restricted", their census counts being combined with those of neighbouring EDs for publication. The census also includes "special" EDs, which were generally large communal establishments such as long-stay hospitals, prisons and other residential addresses which were allocated grid references but not geographical areas. They therefore fall within the geographical limits of conventional area-based EDs. 1981 census EDs were not named, but are uniquely identified by an 8-character alphanumeric code, of which the final two characters are a two-digit number for the ED.

EDs nest within the wards current at the time of the 1981 census, which are identified by a two-character alphabetical code. Wards nest within Districts and Districts within Counties. Wards, Districts and Counties are all individually named. Each District contained one "shipping" ED within one "shipping" ward for the allocation of residents aboard British-registered shipping at the time of the census, although for most districts the population of the shipping ward is 0. These are identifiable by the ward code "SS". Each District is itself identified by a two-character alphanumeric code and each County by a two-digit number, and all these codes combine to make the 8-character code uniquely identifying each ED.

No digital boundaries were created at the time of the 1981 census, although a set of boundaries at the ward level was digitized at the University of Newcastle funded by the then Department of the Environment and a separate ESRC-funded project has recently digitized ED boundaries from a microfiche archive of the OPCS maps. Registered academic users are able to access these datasets through the UKBORDERS service. In addition to these boundaries, a 100m centroid location was allocated to each ED by the OPCS at the design stage and these grid references are available as part of the 1981 small area statistics.

The 1981 census geography coding scheme is not fully recognized in contemporary postcode directories, although the ward codes can often be matched.

Example