Data quality, concepts and methodology

Estimates of population by age and sex for Canada, the Provinces and the Territories

Survey description

This estimates program is used in the calculation of demographic, social and economic indicators (fertility rates, mortality rates, nuptiality rates, divorce rates, unemployment rates, school enrolment rates, etc.) in which the population, or a part thereof, serves as the denominator. These data are used in calculation of weights for use in Statistics Canada's Surveys (Labour Force Survey, Household Facilities and Equipment Survey, General Social Survey, Survey of Labour and Income Dynamics, etc.). They are also used in the determination of the annual level of immigration by the Government of Canada. In addition, the data helps in the preparation of population projections by Statistics Canada, where estimates of population by age and sex are used as the base population. Estimated population counts play a vital role under the Federal-Provincial Fiscal Arrangements and Federal Post-Secondary Education and Health Contributions Act and the Canada Student Loans Act in determining the amounts of federal-provincial/territorial transfers.

Data sources and methodology

Sampling

This survey is a census.

Collection

Data are extracted from administrative files and derived from other surveys.

Postcensal estimates are obtained by the component method, using the most recent census of population (Survey 3901) adjusted to July 1 and for net census undercount as the base population. For example, to estimate the population as of July 1, 2003, demographic events experienced by each cohort since the 2001 Census have been taken into account. To the base population count, births, immigrants and net change of non-permanent residents have been added, and deaths and total emigrants were subtracted. It is also necessary to add the interprovincial net migration. This produces a postcensal estimate of total population as July 1, 2003. The components of population change are estimated on the basis of data gleaned from various sources.

Estimation

Demographic estimates can be categorised as either intercensal or postcensal. Intercensal estimates correspond to estimates between censuses, whereas postcensal estimates correspond to non-census years after the most recent census. In producing up-to-date figures, postcensal estimates are obviously more timely (as there is no need to wait until the release of the next census), albeit less accurate. The production of intercensal estimates involves the retrospective adjustment of past figures with the availability of new census data. Postcensal estimates are obtained by adding the number of births, subtracting the number of deaths and by adding or subtracting the net impact of international and internal migration on the most recent census population adjusted for census coverage error (that is, both census undercount and census overcount). The inclusion of non-permanent residents in the target population dictates that net change in the size of this subpopulation in Canada be added or subtracted from the base period. Estimates of population are first produced for each province and territory, and then summed to obtain an estimate of the population of Canada. Postcensal estimates of population by age and sex are produced following essentially the same approach as that of total population but applied to each age and sex cohort in the population. For more detailed information regarding population estimation methods, see Population and Family Estimation Methods at Statistics Canada, Demography Division, Catalogue No. 91-528-XIE.

Disclosure control

Statistics Canada is prohibited by law from releasing any data which would divulge information obtained under the Statistics Act that relates to any identifiable person, business or organization without the prior knowledge or the consent in writing of that person, business or organization. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

Revisions and seasonal adjustments

Data are revised once a year and after each Census, postcensal estimates are revised to produce intercensal estimates.

Data accuracy

The estimates of population by age and sex contain certain inaccuracies stemming from (1) errors in corrections for net census undercoverage and (2) imperfections in other data sources and the methods used to estimate the components. Errors due to estimation methodologies and data sources other than censuses are difficult to quantify but not insignificant. The more detailed the breakdown of the data, the larger the inaccuracy coefficient becomes. The component totals contain a certain amount of initial error, and the methodology used to classify them by sex and age, produces additional error in the figures at each stage. Nevertheless, the components can be divided into two categories according to the quality of their data sources: births, deaths, immigration, for which the sources of final data may be considered very good; total emigration, non-permanent residents and interprovincial migration for which the methods used may be a more substantial source of error. Lastly, the size of the error due to component estimation may vary by province, sex, and age and errors in some components (births and total emigration) may have a greater impact on a given age group or sex. Intercensal estimates contain the same types of errors as postcensal estimates, as well as errors resulting from the way in which the errors present at the end of the period were distributed, that is, on the basis of the time elapsed since the reference Census.