Factor inputs in U.S. trade

This paper focuses on some open questions in the empirical literature on the factor content of U.S. trade. In a regression analysis on 1963 and 1967 cross-section data, it is found that U.S. trade is exporting the services of human capital and importing the services of raw labor and (marginally) of physical capital. The results are not sensitive to scaling for industry size or to using probit analysis rather than OLS regression. An important implication of the results is that it is inappropriate to aggregate physical and human capital in trade models.