Changing the International Territorial Level geography for Scotland: consultation

Challenges with existing ITLs Boundaries

There are two main challenges for statistics producers with the existing ITL geography definitions in Scotland. These challenges relate to the alignment of Scottish ITL boundaries with existing local authority boundaries, and to unbalanced populations across ITL regions.

Alignment with Local Authority Boundaries

The specification for ITL geographies aims to align with existing administrative boundaires. In particular ITL geographies in the UK are typically based on local authorities. In England, Wales and Northern Ireland for example, all ITL level 1, 2 and 3 regions are based on either local authority areas or aggregations of local authority areas.

The main benefit of doing this is that it makes calculating new statistics at ITL level relatively straightforward in most cases. Given the prevalance of statistics published at local authority level, calculations can in most cases be carried out based on simple aggregations of existing data. This means that additional work to collect data, or to produce estimates by combining statistics for smaller geographical areas is usually not required.

In Scotland however, some existing ITL3 and ITL2 boundaries do not align with local authority boundaries. This means that significant extra work is required to calculate ITL level statistics. In these cases, data must either be built up by aggregating data at a lower level of geography such as Data Zones, or if this data is not available then statistics must be estimated or ‘apportioned’ based on local authority data. This process of aportionment creates additional uncertainy around estimates, and in some case means that statistics at ITL level cannot be produced.

Non-alignment with existing boundaries can also have an impact on avoiding discosure of personal data. Where ITL boundaries do not match local authority boundaries, it may be possible to subtract or ‘difference’ the statistics in order to identify figures for small areas that lie between geographic boundiries. In some cases this can increase the risk of disclosing information about individuals who live in those areas.

Unbalanced populations

The second challenge related to the exisiting ITL definitions relates to unbalanced populations. In order to support comparability of statistics, ITL regions are designed so that their population lies within recommended thresholds. For exisiting ITL regions in Scotland a number of regions fall below these recommended thresholds.

For example, the population of the existing Orkney Islands ITL3 region is just 22,540 according to recent estimates produced by National Records of Scotland. This is significantly below the recommended minimum population of 150,000. This makes it difficult to make meaningful comparisons between regions where there are considerable differences in scale. Further information on the population of existing ITL regions is included in Annex 1.