- Population count: An explanation of the available figures
The Institut de la statistique du Québec produces and publishes population counts derived from three different sources:
- Population Estimates,
- the Census,
- Population Projections.
Some of these figures are produced by the Institut, and others in collaboration with Statistics Canada or by that agency alone. The source of the figures is provided in our tables. Like all other statistics, population counts involve an area of uncertainty, which varies according to the information source, the completeness of the coverage, and the relevance of the indicators chosen to carry out the evaluations. Figures may differ depending on the source and may be revised as indicators are updated.
The purpose of population estimates is 1) to adjust census results in order to account for net undercoverage and incompletely enumerated Indian reserves, and 2) to provide population data between two quinquennial censuses. These estimates are used by the Institut de la statistique du Québec for its demographic analyses.
The most recent counts (2011 to 2016) are postcensal estimates. They are based on the 2011 Census counts, which were adjusted for net undercoverage and incompletely enumerated Indian reserves following coverage surveys. The estimated number of demographic events registered subsequently (births, deaths, and migratory movements) are incorporated annually. For the last available year (2016), the data are preliminary postcensal data, while data for the four previous years (2012 to 2015) are revised postcensal data. The difference between preliminary data and revised/final data is the level of completeness and availability of data for the various components.
The estimates undergo an extensive revision every five years, once the results of the coverage surveys become available. For example, when preliminary data for 2013 were released, Statistics Canada revised the data for 2001 to 2012. Data for 2001 to 2010 then became final intercensal estimates.
Detailed population estimates by age and sex are established each July 1 by Statistics Canada for the provinces and territories and are published every year in September. A few months later, usually in February, Statistics Canada publishes sub-provincial data by CD (census division) and by CMA (census metropolitan area). These data allow the ISQ to produce estimates at the level of administrative regions, RCMs (regional county municipalities) and municipalities, by sex and age or by age group.
The Institut de la statistique du Québec also produces data for the annual decree of the population of municipalities on behalf of the Ministère des Affaires municipales et de l’Occupation du territoire, which is responsible for its preparation. The decree is adopted in December of each year by the Québec government, who then publishes it in the Gazette officielle.
These data are the reference used by municipal governments to prepare budgets, enforce laws and manage government programs. The population estimates used for the decree are slightly different from those published by the ISQ on its website, because the methodology must be adapted since the MAMOT needs to access the data as soon as November.
For historical trends of the population of municipalities, whether for demographic analysis or land use planning purposes, we recommend using the estimates published on the website of the Institut de la statistique du Québec, which provides a chronological series from 1996 to 2016 that is comparable over time, based on the geography on July 1, 2016 for all years.
The population census is a survey of all Canadian households conducted every five years by Statistics Canada. It provides a count of the population at a single point in time, generally in mid-May.
Although an excellent source of information, the Census somewhat underestimates population size and none of its figures are corrected. In 2011, the net undercoverage was in the order of 0.9% for Québec and 2.2% for all of Canada. It varies depending on population and household characteristics. For example, it is greater in the case of 20- to 34-year-olds and slightly higher for men than women.
On its website, Statistics Canada gives several reasons why there is undercoverage in population censuses:
“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 separate 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 current population estimates which take into account net undercoverage.”
Source: Differences between Statistics Canada’s census counts and population estimates, Statistics Canada, accessed February 14, 2017.
Population projections, or demographic perspectives, are simulations of the future. They are based on an in-depth analysis of past and recent trends and on a set of assumptions on the evolution of demographic components: fertility, mortality, external migration, and internal migration. This exercise does not seek to predict the future, but to present a possible future, if trends continue.
Population projections are generally produced every five years, following the release of census data adjusted for undercoverage, which are used as a starting point. However, they may be updated more frequently if an important event so justifies.
The Institut de la statistique du Québec released the Perspectives démographiques du Québec et des régions, 2011-2061 in September 2014. This publication presents a main scenario—Reference Scenario A—which indicates the general trend. Secondary scenarios based on other assumptions which suggest a range of possibilities sometimes quite plausible and sometimes more theoretical, were also developed. Later on, in the fall, projections by RCM for the years 2011-2036 were made available.
Detailed population projections for Québec from 2011 to 2061, and for administrative regions, CMAs and RCMs from 2011 to 2036 are available on the website of the Institut de la statistique du Québec. The website also provides information on the age and sex structure of the population, on annual components (births, deaths, migratory movements), as well as on private households.