Although economic theory predicts an inverse relation between relativewages and immigration-induced supply shifts, it has been difficultto document such effects. The weak evidence may be partly due to samplingerror in a commonly used measure of the supply shift, the immigrantshare of the workforce. After controlling for permanent factors thatdetermine wages in specific labor markets, little variation remainsin the immigrant share. We find significant sampling error in thismeasure of supply shifts in Canadian and U.S. census data. Correctingfor the resulting attenuation bias can substantially increase existingestimates of the wage impact of immigration. (c) 2011 by The University of Chicago. Allrights reserved.

The intergenerational earnings mobility of Canadians born to immigrants is examined using the 2001 Census. A detailed portrait of the Canadian population is offered as are estimates of the degree of generational mobility among the children of immigrants from seventy countries. The degree of intergenerational persistence is about the same for immigrants as for the entire population, and there is more generational mobility among immigrants in Canada than in the United States. We also use quantile regressions to distinguish between the role of social capital from other constraints limiting mobility and find that these are present.