This is a best fit lookup file between middle layer super output areas as at December 2001 and middle layer super output areas and local authority districts as at December 2011 in England and Wales. This product has been provided with a 'change indicator' field, that define the lookup between 2001 and 2011 MSOA. This field indicates which output areas / super output areas have changed between 2001 and 2011. There are four designated categories to describe the changes, and these are as follows: - U - No Change from 2001 to 2011. This means that direct comparisons can be made between these 2001 and 2011 MSOA. - S - Split. This means that the 2001 MSOA has been split into two or more 2011 MSOA. There will be one record for each of the 2011 MSOA that the 2001 MSOA has been split into. This means direct comparisons can be made between estimates for the single 2001 MSOA and the estimates from the aggregated 2011 MSOA. - M - Merged. 2001 MSOA have been merged with another one or more 2001 MSOA to form a single 2011 MSOA. This means direct comparisons can be made between the aggregated 2001 MSOAs’ estimates and the single 2011 MSOA’s estimates. - X - The relationship between 2001 and 2011 MSOA is irregular and fragmented. This has occurred where 2001 MSOA have been redesigned because of local authority district boundary changes, or to improve their social homogeneity. These can’t be easily mapped to equivalent 2011 MSOA like the regular splits (S) and merges (M), and therefore like for like comparisons of estimates for 2001 MSOA and 2011 MSOA are not possible. Each 2001 MSOA with an ‘X’ code is best-fitted to a 2011 MSOA by plotting the 2001 MSOA’s centroid into a 2011 MSOA boundary. However, this does not imply an exclusive 1:1 relationship with a 2011 MSOA, as it will also have a relationship with fragments of other 2011 MSOA; the lookup is provided here so that all 2001 MSOA are included in the lookup (File Size 546KB).REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/MSOA01_MSOA11_LAD11_EW_LU_4d62b7319b914e52bb640ccd5d7977b6/FeatureServer

For more information and an overview of best-fitting follow this link - https://geoportal.statistics.gov.uk/datasets/f0aac7ccbfd04cda9eb03e353c613faa/about