This paper investigates the link between the trend in the returns to education and foreign competition in concentrated industries. We argue that the impact of foreign competition on the relative wages of less skilled workers depends on the market structure of the industry penetrated. The empirical evidence indicates that employment changes in a small group of trade-impacted concentrated industries can explain not only part of the aggregate rise in wage inequality in the United States, but also some of the differences in the trends in wage inequality across metropolitan areas.

This paper examines the short-run dynamics of manufacturing costs by detailing how plants in the U. S. automobile industry change output. Weekly data show a variety of margins on which firms adjust production. These margins, which are distinct from the usual factor demand choices, differ in their lumpiness, their adjustment costs, and their variable costs. The existence of these margins explains several empirical puzzles of output fluctuations. Using a theory of the short-run dynamic cost function, we are able to infer some of the characteristics of the underlying cost function from the dynamic behavior of the different margins.