The changes to census subdivisions (CSDs) between the 2006 edition of the SGC and the 2011 edition are provided in concordance tables. In addition to the changes of CSD name, CSD type and revision of SGC code, the concordance table SGC 2006 – SGC 2011 presents the CSDs that have been deleted (change code 4) and the CSDs that have lost land through the creation of new CSDs (change code 6) whereas the concordance table SGC 2011 – SGC 2006 presents the newly created CSDs (change code 1) and the complete annexations of CSDs by another CSD (change code 5A).
In each concordance table, there is only one entry or CSD on the left-hand side with one or many entries (CSDs) on the right-hand side. The change code allows users to exactly know what part of the left-hand side entity has changed. Change codes 2 and 2C, 3 and 3C, 23 or 7 and 7C respectively indicate a change of CSD name, CSD type, CSD name and type or revision of SGC code. Change codes 1, 4, 5A or 6 respectively indicate a newly created CSD, a CSD deleted, a complete annexation of a CSD by another CSD, or a CSD created out of another CSD.
Contrary to the SGC 2006 – SGC 2011 and SGC 2011 – SGC 2006 concordance tables, the table of annual changes from 2006 - 2011 uses two change codes to explain the annual changes to CSD codes, names and types between 2006 and 2011. The former state of the census subdivision appears on the left-hand side while its revised state is on the right-hand side. The change codes 2, 2C, 23, 3, 3C, 7 and 7C are repeated on both sides while the others are combined to show different changes. For a dissolution (code 4) on the left-hand side, there is a creation of new CSD (code 1) or a complete annexation of a CSD by another CSD (code 5A) on the right-hand side. A CSD that has lost part of its land through the creation of a new CSD has a code 6 on the left-hand side and a code 1 for the new created CSD on the right-hand side. The symbols (** and ***) attached to SGC codes on the left-hand side are included to inform users that these SGC codes are new entities created after January 1st, 2006 which were updated after their creation.
The change codes used here follow the definitions presented in the Standard Geographical Classification (SGC) 2011, introduction to the classification. The exceptions are change code 6 that only shows the creation of a new CSD from a part of another CSD and change code Y, introduced here and used in concordance tables SGC 2006 – SGC 2011 and SGC 2011 – SGC 2006. Code Y shows the remaining part of the CSD from which a part has been lost or the common part of the combination that now makes up the new CSD on account of the complete annexation of a CSD.