1981/1986 comparability indicator
A single digit numeric code which indicates whether the 1986 Census collection district is comparable with a 1981 Census collection district. Loss of comparability can be caused by a number of factors but the main ones are changes to CD boundaries to align them with readily identifiable topographical features, LGA boundary changes, changes necessary to accommodate urban growth, and changes necessary to enable population figures for new or modified statistical areas to be provided.
The code values used are:
0 = CD is perfectly comparable i.e. the CD has exactly the same boundary.
1 = CD where the population and dwellings are not affected even though there has been a change in the CD boundary.
2 = CD is comparable within a 10% dwelling limit i.e., a boundary change has occurred but no more than 10% by number of 1981 dwellings in the CD have been added to or subtracted from the old CD in the boundary change.
3 = CD is comparable except that a special dwelling(s) such as a new hospital, etc., has been taken out and made a separate CD or CDs. In this instance the boundary must remain unchanged for the 'outer' CD.
4 = CD is not comparable due to a split of the 1981 CD into two parts (the old boundary being retained around the two new parts).
5 = As for 4 above except that the split has involved the creation of three or more parts.
6 = CD is not comparable because of a split with variations being made to all or part of the existing boundaries.
7 = CD is not comparable because it is an amalgamation of two 1981 CDs to give a 1986 CD (using the same outer boundary).
8 = CD is not comparable because it is an amalgamation of three or more 1981 CDs (using the same outer boundary).