There is a strong connection between per worker productivity and metropolitan area population, which is commonly interpreted as evidence for the existence of agglomeration economies. This correlation is particularly strong in cities with higher levels of skill and virtually non-existent in less...

Empirical research on cities starts with a spatial equilibrium condition: workers and firms are assumed to be indifferent across space. This condition implies that research on cities is different from research on countries, and that work on places within countries needs to consider population,...

Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...

Recent theories of economic growth, including Romer (1986), Porter (1989) and Jacobs (1969), have stressed the role of technological spillovers in generating growth. Because such knowledge spillovers are particularly effective in cities, where communication between people is more extensive, data...

A theoretical model is developed and applied to the North American auto industry, motivated by the possibility of US-Mexico free trade. Special features of the model include (1) significant scale economies at the plant level, (2) imperfect competition among firms, (3) joint ownership of plants...

Beginning in the early 1980s, theoretical analyses have incorporated the multinational firm into the microeconomic, general-equilibrium theory of international trade. Recent advances indicate how vertical and horizontal multinationals arise endogenously as determined by country characteristics,...

Theoretical and applied work in industrial-organization approaches to international trade typically assume either that there are fixed numbers of firms, or that there is free entry and exit with a continuum of firms. This paper makes a first step toward a more realistic approach in which firms...

Regional trade agreements must specify domestic-content rules (rules of origin) that define the conditions under which a good qualifies as 'domestic' and so may be freely traded within the block. The paper analyzes such rules, focussing in particular on oligopolistic industries in which foreign...