The methodology used to create the OA lookups is based on the distribution of 2011 Census population. A median average of each OA's household grid references, weighted by the population at each household has been used to create a population weighted centroid for each OA. This centroid has been used to allocate the OA and all its associated statistics to any higher geographies. Information on the percentage of an OAs population that falls into the higher geography has also been included in this best-fit lookup file. A ‘best-fit percentage’ indicator has been included in this lookup, to support an understanding of the actual relationship between the OA and the higher geography to which it has been best-fitted. This ‘best-fit percentage' indicator has been calculated by working out the percentage of the OA population that falls exactly within the output geography's boundary. This is calculated by plotting the grid references of the households into the output geography's digitised boundaries and aggregating the population that actually falls within the best-fitted geography's boundary. 100 indicates that all the OA population actually fell within the best-fitted boundary. A value of 90 means that the OA boundary is split across the output geography's boundary and that 90% of the OA population actually fell within the geography the OA was best-fitted to. Only the higher geography to which the OA has been allocated will be given a percentage match. (File Size 12.3MB).
Field Names – OA11CD, PCO11CD, PCD11NM, PCO11NMW, OA11PERCENT, SHA11CD, SHA11NM, OA11PERCENT1
Field Types – Text, Text, Text,
Text, Text, Text, Text, Text
Field Lengths – 9, 9, 37, 37, 3, 9, 24, 3