The geographic harmonisation of Scotland's small area census data, 1981 to 2011

Previous research in Scotland used a merging approach to combine census boundary data for geographies specific to 1981, 1991 and 2001 to create Consistent Areas Through Time (CATTs) for the analysis of health and social data for small areas. In this paper, we adopt the same methodology to integrate the 2011 Scottish Output Areas to the CATTs. First, we overlaid the 2001 Output Areas upon the 2011 Output Areas to create SUPER OAs, which were then combined with SUPER EDs, which represented a consistent small area geography for 1981 and 1991. This resulted in 8,548 CATTs providing a consistent geography for the 1981, 1991, 2001 and 2011 Censuses in Scotland. We demonstrate the utility of the CATTs by exploring the correlations between deprivation, the proportion of the population who were permanently sick and those with degree qualifications, across the 4 censuses, a research angle impossible without consistent geographies. We have provided a resource that enables users to deepen their understanding of small area social changes in Scotland between the 1981 and 2011 Censuses.