This paper estimates the elasticity of substitution between capital and skill using variation across U.S. counties in immigration-induced skill-mix changes between 1860 and 1930. We find that capital began as a q-complement for skilled and unskilled workers, and then dramatically increased its...

The non-constancy of factor shares is drawing the attention of many researchers. We document an average drop of the labour share of 8 percentage points for eight European countries and the US between 1980 and 2007. We investigate theoretically and empirically two mechanisms: the substitution...