Determinants of the structure of U.S. foreign trade, 1958–1976

The Heckscher-Ohlin model with three direct-factor inputs is borne out for U.S. net exports of manufactures in annual cross-section regressions for 1958–1976. The coefficient on unskilled labor became significantly more negative over the period, and there is evidence that the negative sign on physical capital may reflect the inclusion of natural resource industries. Further analysis based upon 1960 and 1970 census years suggests the importance as well of skill and technological variables. Calculations of the total factor requirements of U.S. trade uphold the Leontief paradox for 1958 but not for 1972.