The supply and price of skilled labor relative to unskilled labor have changed dramatically over the postwar period. The relative quantity of skilled labor has increased substantially, and the skill premium, which is the wage of skilled labor relative to that of unskilled labor, has grown significantly since 1980. Many studies have found that accounting for the increase in the skill premium on the basis of observable variables is difficult and have concluded implicitly that latent skill-biased technological change must be the main factor responsible. This paper examines that view systematically. We develop a framework that provides a simple, explicit economic mechanism for understanding skill-biased technological change in terms of observable variables, and we use the framework to evaluate the fraction of variation in the skill premium that can be accounted for by changes in observed factor quantities. We find that with capital-skill complementarity, changes in observed inputs alone can account for most of the variations in the skill premium over the last 30 years.

We show that a theory of earnings and wealth inequality, based on the optimal choices of ex ante identical households that face uninsured idiosyncratic shocks to their endowments of efficiency labor units, accounts for the U.S. earnings and wealth inequality almost exactly.

Global financial imbalances can result from financial integration when countries differ in financial markets development. Countries with more advanced financial markets accumulate foreign liabilities in a gradual, long-lasting process. Differences in financial development also affect the composition of foreign portfolios: countries with negative net foreign asset positions maintain positive net holdings of nondiversifiable equity and foreign direct investment. Three observations motivate our analysis: (1) financial development varies widely even among industrial countries, with the United States on top; (2) the secular decline in the U.S. net foreign asset position started in the early 1980s, together with a gradual process of international financial integration; (3) the portfolio composition of U.S. net foreign assets features increased holdings of risky assets and a large increase in debt. (c) 2009 by The University of Chicago. All rights reserved..