Since 1961, after each census collection period, Statistics Canada has conducted rigorous studies to assess the quality of its census population counts. The census attempts to enumerate every person residing in Canada on the reference day, which was May 11 for the 2021 Census. The Census Undercoverage Study and the Census Overcoverage Study measure, respectively, the number of people missed and the number of people enumerated more than once by the census. Although census data are not adjusted by the results of the coverage studies, both studies are used to produce updated demographic estimates. These estimates are also made available in today's release by the Demographic Estimates Program.
For the 2021 Census, the net undercoverage rate (percentage of people missed less those enumerated more than once) was 3.1%. This rate is slightly higher than that for the 2016 Census, which was 2.4%.
In the context of the 2021 Census, unprecedented challenges arose due to the COVID-19 pandemic, and yet the census was a resounding success thanks to Canadians and to all Statistics Canada employees who contributed to the delivery of high-quality statistical information.
Note to readers
Overcoverage was first measured in the 1991 Census. It was also the first census where the coverage errors were measured for the territories.
Studies have shown that the error due to the enumeration of people who should not have been is much smaller than the one due to people being counted more than once. It is therefore only the latter type of overcoverage that is estimated.
Comparisons with previous censuses should be made with caution, as the methodology for both the census and its coverage studies changes with the objective of producing the best information possible at each cycle.
Reference
Contact information
For more information, or to enquire about the concepts, methods or data quality of this release, contact us (toll-free 1-800-263-1136; 514-283-8300; infostats@statcan.gc.ca) or Media Relations (statcan.mediahotline-ligneinfomedias.statcan@statcan.gc.ca).