The objective of every census is to provide detailed information at a single point in time on the demographic, social and economic conditions of the population. One of its goals is to enumerate the entire population on Census Day.

Inevitably, however, some people are not counted, either because their household did not receive a census questionnaire (for example, a household living in a separate apartment in a house) or because they were not included in the questionnaire completed for the household (for example, a boarder or lodger).

Some people may also be missed because they have no usual residence and did not spend census night in any dwelling. On the other hand, a small number of people may also be counted twice (for example, a student living away from home).

To determine how many individuals were missed or counted more than once, Statistics Canada conducts post-censal coverage studies of a representative sample of individuals.

The results of these studies provide information used to adjust the census counts for the purpose of producing current (quarterly and annual) population estimates which take into account net under-enumeration in the census.

In 1996, after adjustment for net under-enumeration, the population estimate for Canada was 2.6% higher than the population enumerated in the census.

The studies of enumeration of the 2001 Census will be completed early in 2003, and will be used to revise and update the population estimates.