Technical Guide on Demographic Estimates at Statistics Canada
Chapter 4
Births

Vital statistics for Canada have been published by the Dominion Bureau of Statistics (later Statistics Canada) since the first annual report for vital statistics in 1921. Prior to 1920, vital statistics in Canada were collected in an inconsistent manner by some provincial governments. The Dominion Bureau of Statistics was created following The Statistics Act, 1918 with an order-in-council in 1919 establishing a cooperative national vital statistics system including eight provinces.

Other provinces and territories joined the cooperative national reporting system over time. By 1956, all provinces as well as Yukon and the Northwest Territories were included in regular tabulations with Nunavut being separate from the Northwest Territories following the establishment of the territory in 1999.

In order to produce demographic estimates according to the cohort-component method, the Demographic Estimates Program (DEP) adds births to the base population as part of the calculation. For the DEP, the term birth refers to live births, excluding stillbirths.

Definitions and concepts

Data for births comes from Statistics Canada’s Canadian Vital Statistics - Birth Database (CVSB). The registration of all live births is mandatory according to the Vital Statistics Acts (or equivalent legislation) of each of the provinces and territories in Canada. A live birth is a birth where, following separation from the mother, there is any evidence of life, such as breathing, beating of the heart, pulsation of the umbilical cord, or definite movement of the voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached. The DEP does not include stillbirths in the demographic estimates, which are births (after 20 weeks of gestation or with a weight of over 500 grams) that do not show any such evidence of life.

The central vital statistics registry in each province and territory provides Statistics Canada with the births data which is then used in the demographic estimates.

The conceptual universe of the Birth Database is births to Canadian resident women occurring anywhere in the world while its target population is births to Canadian resident women occurring in Canada. The actual (survey) population of the Birth Database includes births to Canadian resident women and non-resident women (visitors) occurring in Canada.

The DEP excludes births of visitors from the demographic estimates. Births and adoptions to Canadian citizens that occur abroad are included in the demographic estimates at the point that the child (or adult) enters Canada. Adoptees enter Canada through the immigration or returning emigrant components, depending on the type of adoption process, while people born to Canadian citizens abroad would enter the population estimates as returning emigrants if they come to live in Canada.

The DEP counts births according to the place of residence of the mother. This is because the birth affects the population of the place of residence and not the province in which the birth occurred.

Final estimates

All levels of the demographic estimates (preliminary, updated and final) are produced using births data from the CVSB. For the final estimates, the numbers of births are taken directly from the annual births data in the CVSB. This usually happens within two to three years of the reference date, at the point at which the data in the CVSB is deemed by the DEP to be sufficiently complete.

In recent years, the duration of data collection for the CVSB has been shortened, such that fewer births may be captured at the time of each annual release of data. The data for the CVSB is revised and updated each year and the DEP includes the revised numbers until the point at which the estimates become final. The births estimates may also be revised at the time of the rebasing of the population estimates after each quinquennial census, when the final postcensal population estimates become final intercensal. This would happen if the birth data from the CVSB had been further revised after they became final for the DEP.

The DEP cannot finalize the births estimates until they are considered to be sufficiently complete. Following the recent changes in release timing for the CVSB, the time between the reference date and the finalization of the births estimates may be lengthened. Data received from the CVSB are continually being reviewed by the DEP for completeness.

Data sources

The births data for the final estimates comes directly from the Canadian Vital Statistics - Birth Database (CVSB) which is an administrative survey that collects information on live births on an annual basis from all provincial and territorial vital statistics registries. The main form for the registration of a live birth is completed by the parents, who are responsible for filing it with the local registrar. Most provinces and territories also require physicians (or other birth attendants) to report all births.

The central vital statistics registry in each province and territory provides data from the birth registrations to Statistics Canada for inclusion in the CVSB on a continual basis. Beginning with births occurring in 2008, the provinces have been able to send data electronically to Statistics Canada via the National Routing System (NRS) although the effective date for this method of transmission varies by province. The territories send paper information which is converted to electronic format at Statistics Canada.

Subsequent changes to registrations due to errors, amendments, or omissions are transmitted to Statistics Canada when this information becomes available. However, changes received after a cut-off date are not reflected in published data.

Error detection and imputation are conducted for the CVSB following set rules, however due to the high quality of the data received, few records are imputed annually. Since the registration of births is a legal requirement in each Canadian province and territory, reporting is virtually complete. Undercoverage is thought to be minimal but is being monitored. Statistics Canada does receive late registrations, often five years after the birth, when a birth certificate is required for school registration.

Non-registration and overcoverage are minimal. Births to visitors are registered in the CVSB, but excluded in the estimates by the DEP. Any duplicate birth records are identified and removed.

Method

To create the final estimates, number of births that occurred between the date on which the base population was established and the reference date are added to the base population.

Preliminary estimates

Since the final births from the CVSB are not available at the time that the preliminary population estimates are produced (approximately three months after the reference date), the preliminary births are estimated by applying fertility rates based on the last year of final data to the population, according to the age group of the mother.

Data sources

The fertility rates by age group of the mother are produced from the last year of final data, which is supplied by the CVSB for most provinces and territories. However, preliminary and updated data for Quebec, British Columbia, and Yukon are provided by the Institut de la statistique du Québec (ISQ), BC Stats, and the Yukon Bureau of Statistics (YBS), respectively. The final estimates for all provinces and territories (including Quebec, British Columbia, and Yukon) are taken from the CVSB, when they are available and complete.

Method

The following formulas are used to generate the quarterly preliminary estimates of births at the provincial and territorial levels.

By quarter, for each province and territory, by mother’s age group at the beginning of the quarter, the equation is:

Equation 4.1:

$$B_{(t,t+i)}^{a_m}=\left(\frac{{}^{f}B{}^{a_m}}{{}^{f}P{}^{a_w}}\right)x{P}_t^{a_w}$$

Where:

Then the estimate of the total number of births is calculated as follows:

Equation 4.2:

$$B_{(t,t+i)}={\displaystyle \sum _a{B}_{(t,t+i)}^{a_m}}$$

Updated estimates

Until 2020, when the COVID-19 pandemic resulted in delayed reception of birth registrations by Statistics Canada which required adjustments to the typical method, all updated births estimates were calculated in the same manner as the preliminary estimates, using fertility rates applied to the population. The data from the CVSB would replace the updated estimates for all provinces and territories when they became available and the estimates would become final.

However, as the CVSB collection period has shortened, the DEP has sometimes observed that the data in the CVSB are complete for some provinces and territories and incomplete for others. In such cases, the updated birth estimates are produced by directly using the CVSB birth counts for provinces and territories where the data are considered complete. For those where the data are considered incomplete, the birth estimates are produced using fertility rates from the last year of final data, special adjustments, or a combination of both. Birth estimates become final only once the CVSB birth counts are considered complete for all provinces and territories and are used directly for all jurisdictions.

Births estimates by gender and sex at birth

The DEP currently publishes all tables according to gender, rather than sex at birth, consistent with changes introduced in the 2021 Census of Population. The data provided to the DEP from the CVSB as well as from the ISQ, have information on sex at birth and not gender. The sex at birth variable for births is used by the DEP and released as gender, consistent with current guidelines.

The final estimates of births by gender are produced using the sex at birth distribution of births in the CVSB directly. The updated and preliminary estimates by gender are produced using an average gender distribution from the past ten years of final data in the DEP (the birth estimates for the ten most recent years produced entirely using the CVSB – those that are considered complete for all provinces and territories). The annual preliminary and updated data for Quebec provided by the ISQ are broken down by age and sex and that distribution is used directly by the DEP to produce preliminary and updated estimates of birth by gender for this province.

Subprovincial births estimates

For the final subprovincial estimates, the number of births at the census division (CD), census metropolitan area (CMA) and census agglomeration (CA) levels are taken directly from the CVSB. They are then adjusted to the provincial and territorial totals using two-way raking to ensure their concordance. The postal codes of individuals are geocoded using PCCF+^Note so that they are assigned a CD and CMA or CA geographic.

For the preliminary subprovincial and updated estimates, the preliminary and updated provincial or territorial estimates are distributed according to the most recent known subprovincial distribution, derived from the CVSB, to produce estimates by region. They are then adjusted to the provincial and territorial totals using two-way raking to ensure their consistency.

For Quebec, British Columbia and Yukon, the subprovincial preliminary and updated estimates are the total births supplied by the ISQ, BC Stats, and YBS respectively, which are distributed according to the most recent final subprovincial breakdown. The ISQ provides their subprovincial estimates by age and sex and also by subprovincial region, whereas BC Stats and the YBS provide counts for total births only for the province or territory. As with the provincial and territorial estimates, final subprovincial estimates for Quebec, British Columbia, and Yukon are taken from the CVSB when they are available and complete.

Limitations

The preliminary estimates (and some updated estimates) are based on the fertility rates by the age of the mother from the last year of final estimates, provided by the CVSB. Canada has been experiencing a generally declining fertility rate for several decades.^Note Thus, the longer the interval between the last year of final estimates and the preliminary estimates, the more likely that the fertility rate has changed. This may lead to a overestimation of the number of births in the preliminary or updated estimates calculated by applying fertility rates. However, an underestimation may also occur if the fertility rate were to increase.

The potential over- or underestimation of the number of preliminary or updated births may be a larger concern if there are widespread, unpredictable, societal influences on the usual patterns of change in the fertility rate.^Note The DEP measures the difference between the preliminary and final estimates (known as precocity error) to ensure the preliminary estimation technique continues to be appropriate.

Births are received through the NRS on a continual basis and the CVSB is updated annually with a new year of data and with historical updates to past data. It is possible that some of the data not included in the first release of data in the CVSB are non-random in distribution. This may occur due to such issues as outages in the NRS affecting only one jurisdiction or staffing shortages among one or more provincial or territorial registers. To ensure the quality and completeness of the births estimates in the DEP, all data received from the CVSB are reviewed. Methodological adjustments are applied in the case that missing data would affect the quality of the population estimates.^Note