This paper surveys key developments in the theory of international migration and international trade, and provides a few stylized facts. International migration, in many important cases, such as cross-country differences in productivity, can be a complement to international flows of commodities....

The paper provides a reconciliation of Lucas' paradox, based on fixed setup costs of new investments. With such costs, it does not pay a firm to make a small' investment, even though such an investment is called for by marginal productivity conditions. Using a sample of 45 developed and...