Components--Population and Migration

Background

Canada is a nation of immigrants.  At the peak of immigration, in the decade 1901-1911, the total number of immigrant arrivals amounted to about 25% of the average population over the decade.  Even now, the foreign-born represent more than 15% of the total population.  Immigration continues to make a crucial contribution to Canada’s continued population growth despite sizeable emigration – principally to the United States.  The significance of emigration is demonstrated by noting that, in 1911, the foreign-born – including all remaining earlier immigrants – represented 22% of the total population despite extremely high rates of immigration in the preceding decade.  Net immigration, although positive for most of the last century, has not always been so.  That said, there is still considerable uncertainty about the actual level of emigration over the last 100 years.  There has never been a count of emigrant departures that corresponds to the careful record made of immigrant arrivals. 

Sources:
Historical statistics of Canada: Immigrant Arrivals in Canada, 1852 to 1977
CANSIM: Table 051-0004, Annual Immigrants and Emigrantsà

Immigrants commonly arrive when they are adults with substantial education or work experience and with already established family ties – both of which are important influences on their subsequent life in Canada.  Typically, the characteristics of immigrants differ from those of native-born Canadians and those of the populations in their countries of origin.  For example, recent immigrants are likely to be highly educated whether compared with the Canadian average or that of any other country.  For those reasons, special attention must be given to the immigrant population, beginning with a determination of the age and time at which they arrive.  It is a special challenge to model the Canadian population without at the same time modeling the rest of the world.

Historically, interprovincial migration was related to immigration.  Prior to World War I, the Prairie provinces were being settled, both by immigrants and by migrants from the Eastern and Central provinces.  Since at least the Depression, migration has become more often an individual or family choice involving comparison of unique opportunities in different provinces.  Presently, as the figure below illustrates, migration trends can differ for each pair of provinces.  Data for the earliest years are limited; in some cases, all that is available are Census data comparing province of birth with province of residence, which is indicative of lifetime migration.  Currently, more direct and more timely data are available from administrative files. 

Sources:
CANSIM: Derived from Table 051-0019 – Interprovincial migrants, by province or territory of origin and destination

LifePaths implementation

LifePaths models individuals from their birth.  When creating a new individual, place of birth (in a specified province or territory or outside Canada), sex and date of birth are assigned.  If they were born outside Canada, their province of entry to Canada and age of immigration are also assigned.  Given that the earliest birth occurs in 1872, LifePaths can simulate a complete population aged 0 to 99 starting in 1972.  By default, LifePaths simulations closely approximate official estimates of the Canadian population by age, sex and province in each year over the period 1972 to 1998.  The population modeled does not include non-permanent residents, a large number of which are foreign students.

There are four types of migration modeled: immigration, emigration, returns to Canada and interprovincial migration.  All migration is modeled at the family level: if one family member migrates, their spouse and dependent children also migrate.  Immigrants become Canadian citizens three years after their arrival in Canada.

Emigration is also modeled.   All individuals in the model who are currently living in Canada have a probability that they might emigrate.  Factors that influence emigration include age, sex, province of residence, calendar year, immigrant status and the year of immigration (for immigrants). 

Canadian citizens who emigrate can also return to Canada.  This means that immigrants who leave the country after having lived in Canada for three years or more as well as individuals born in Canada can emigrate and then return to Canada.  However, immigrants who leave Canada before becoming Canadian citizens are not eligible to return to Canada.  Factors that influence a return to Canada include age, sex, year, last province of residence, immigration status and year of immigration (for immigrants).
 
As well as moving in to and out of Canada, people in the model and their families can move from one province to another. (Both provinces and territories are represented, although the LifePaths representation of the Northwest Territories also includes Nunavut.) A base probability of moving between each pair of provinces serves as the benchmark for estimation of family migration probabilities for each of five family types: husband-wife couples, common-law couples, single males, female lone parent and other single females.  These probabilities incorporate the influence of factors such as age, education and whether or not a person would be moving from or back to their province of birth.  Two additional factors are the current province of residence and the province of birth.  Return migration to the province of birth proved to be among the strongest of the migration patterns uncovered in the analysis of migration data.  Within a simulation, the base probability of moving between each pair of provinces varies from year to year.

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The population in each province at any moment of time is therefore determined by several factors: births, deaths and migration flows either within Canada or internationally.

Data sources

The historical series of births by sex and province that are used to initialize simulations were derived from the 1911 and 1921 Censuses together with annual birth registrations between 1921 and 1998 as well as from immigration records.  For the period prior to 1921, the 1921 Census population was ‘reverse survived’: the number of births that would have had to occur to produce the observed number of survivors in 1921 was determined using mortality probability estimates.  For 1921 to 1971, historical population estimates by age, sex and province were used.  Special estimates for Newfoundland were derived using the 1911, 1921 and 1935 Censuses of Newfoundland. 

For the period 1972-1998, the official population estimates were used.  These were available by age, sex and province and consist of the following components: total population, non-permanent residents, immigrants, emigrants, returning Canadians and internal migrants.  Historical lifetime internal migration data was based on decennial Census data from 1911 to 1971.  Base probabilities of individuals moving between each pair of provinces were derived using the Family Allowance-Child Tax Credit data (1972-1996).  Estimates of family level migration probabilities were obtained (using the base probabilities as benchmarks) from 1991 and 1996 Census data on place of residence one year prior to the Census.