A best-fit lookup between enumeration postcodes, Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD) as at 31 December 2011 in England and Wales. Postcodes are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. Enumeration postcodes are a sub-OA geography used only for the publication of estimates of males, females and households in the 2011 Census. The 2011 Census enumeration postcodes consist only of valid unit postcodes as at May 2011.