According to economists, in the 1980s and 1990s, immigration of low-skilled workers may have increased the labor supply of highly skilled women, and immigration of highly skilled workers may have increased the rate of innovation in the United States.

Cities initially more specialized in older technologies may have had more difficulty adapting to newer technologies because skills in initially dominant industries were not useful to new industries.

Migration incentives for working-age and retired individuals are quite different and are sensitive to the level of human capital within the family.

Mortality rates no longer rise sharply in recessions.

In the United States, wide disparity exists in the health of individuals with different levels of education