Dictionary, Census of Population, 2021
Census subdivision—previous census

Definition

'Census subdivision—previous census' refers to the census subdivisions (CSDs) as of January 1, 2016 (the geographic reference date for the 2016 Census). A "best fit" linkage is established between dissemination blocks for the 2021 Census and CSDs (municipalities) for the 2016 Census. This linkage ensures that data from the current census can be tabulated for the CSDs from the previous census.

Reported in

2021, 2016, 2011, 2006 and 2001

Remarks

The boundaries and names of census subdivisions (municipalities) can change from one census to the next because of annexations, dissolutions and incorporations. These changes can result in fewer, larger census subdivisions (CSDs) and more complex historical data analyses. The concept of "CSD—previous census" was established to provide a means of tabulating current census data according to CSDs as they were delineated for the previous census.

Census data are tabulated for each standard geographic area by aggregating the data for individual dissemination blocks. Dissemination blocks respect the boundaries of CSDs for the current census (2021 Census), but do not necessarily respect the boundaries of CSDs for the previous census (2016 Census). To facilitate the tabulation of 2021 Census data for the CSDs as they existed for the 2016 Census, the 2021 dissemination block representative points are overlaid onto the previous census CSD boundaries. The goal is to ensure that at least one dissemination block is linked to each previous census CSD. In a few cases, there is not an exact match—that is, some dissemination blocks straddle two or more CSDs from the previous census, but can only be linked to one CSD. For these cases, a "best fit" approach is used to ensure that the representative point for at least one dissemination block is linked to every previous census CSD. Thus, reasonably accurate tabulations of 2021 Census data can be produced for the CSDs as of January 1, 2016 (the geographic reference date for the 2016 Census).

Refer to the related definitions of Census Subdivision (CSD), Dissemination Block (DB), Geographic Reference Date and Representative Point.

Changes prior to the current census

Not applicable