The 2016 Census counted 35,151,728 people in Canada during the national enumeration with reference day May 10, 2016. This count is lower than the preliminary postcensal population estimate of 36,207,822 people calculated for the same reference date. A difference between the two figures is expected and the recent difference is similar to what was observed for previous censuses. This note outlines why there are differences between census counts and population estimates.
The objective of a census is to provide detailed information on the population at a single point in time. In this respect, one of its goals is to enumerate the entire population. Inevitably, however, some people are not counted, either because their household did not receive a census questionnaire (for example, if a structurally separated dwelling is not easily identifiable) or because they were not included in the questionnaire completed for the household (for example, the omission of a boarder or a lodger). Some people may also be missed because they have no usual residence and did not spend census night in any dwelling. In contrast, a small number of people may also be counted more than once (for example, students living away from home may have been enumerated by their parents and by themselves at their student address).
To determine how many individuals were missed or counted more than once, Statistics Canada conducts postcensal coverage studies of a representative sample of individuals. Results of these studies in combination with the census counts are used to produce population estimates which take into account net undercoverage.
Postcensal coverage study results are usually available two years after enumeration date. These will be used to revise and update the population estimates based on the 2016 Census results. Consequently, a series of revised population estimates for the period 2011 to 2018 will be disseminated in September 2018.
One of the advantages of the census is to provide counts for small regions for which demographic estimates are not available or are less precise. On the other hand, population estimates provide more frequent measures of population counts for more aggregated levels of geography. In addition, estimates are used to measure the evolution of the population between censuses and provide explanations behind the population growth. The demographic estimates are available on a quarterly and annual basis at the national, provincial and territorial levels as well as for some subprovincial levels.