A substantial number of Canadian immigrants do not plan to stay here permanently, while more than a third of young male workers leave within 20 years of their arrival, according to Statistics Canada.

A federal agency study examined the behaviours of men who were 25 to 45 when they arrived in Canada starting in 1980.

The study found that about 35 per cent departed within 20 years, with about 60 per cent of those leaving within the first year of arrival.

Immigrants' countries of origin, their economic qualifications and the business cycle had a strong bearing on their decisions to stay or leave.

For example, highest departure rates were among the group that arrived in 1980 at the onset of a business cycle downturn, and those who arrived around the 1990 recession, the study said.

People are allowed to migrate to Canada in a number of ways.

They include through a points system, in which people are classified under the categories of business class, skilled worker class and assisted relative class, on the basis of family ties or a refugee process.

The study found higher departure rates among immigrants who were admitted in the business and skilled-worker classes, noting that the global labour market makes their mobility easier.

Refugee claimants had the lowest departure rates.

Newcomers from the United States and Hong Kong were most likely to leave Canada, with about half leaving within 10 years. Newcomers from Europe or the Caribbean, in contrast, were about half as likely to leave.

Language was also a factor. Bilingual immigrants and those fluent in French had 25 per cent shorter stays. Married immigrants stayed 25 per cent longer than single immigrants.