The influx of a greater share of higher-educated immigrants to Canada tends to limit the gap between high and low incomes, according to a Statistics Canada study released Friday.

However, the wage gap is exacerbated in the United States, where a greater proportion of immigrants aren't as skilled.

Statistics Canada said that based on 2001 data, about four in 10 immigrants arrivedwith more than an undergraduate university degree. In the U.S., that figure was about two in 10.

The greater proportion of higher-skill workers coming to Canada limits upward pressure on upper-end wages, while the influx of less-educated workers into the U.S. puts downward pressure on lower-end wages.

The difference lies in the two countries' divergent policies on immigration.
While Canada has put more emphasis since the 1960s on higher-skill immigrants, U.S. policy has leaned towards family reunification, which resulted in a disproportionate number of low-skilled immigrants," Statistics Canada said.

In addition, illegal immigration to the U.S. since 1965— more than half estimated to have been from Mexico—has also contributed to the tendency for immigrant workers to be lower skilled.

An estimated 10.3 million immigrants to the U.S. since 2005 have entered illegally, Statistics Canada said.

The study found that immigration played a role in the seven per cent drop in real weekly wages experienced by workers with more than a university undergraduate degree in Canada between 1980 and 2000.

Over that period, the immigrant share of all workers with more than a university undergraduate degree in Canada increased. Between the 1986 and 2001 censuses, this share rose from 32.5 per cent to 38.2 per cent.