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...

What are the sovereign rights of nations in an interdependent world, and to what extent do these rights stand in the way of achieving important international objectives? These two questions rest at the heart of contemporary debate over the role and design of international institutions as well as...

We consider the purpose and design of trade agreements in imperfectly competitive environments featuring firm-delocation effects. In both the segmented-market Cournot and the integrated-market monopolistic competition settings where these effects have been identified, we show that the only...

When markets are imperfectly competitive, trade policies can alter the terms of trade, shift profits from one country to another, and moderate or exacerbate existing distortions that are associated with the presence of monopoly power. In light of the various ways in which trade policies may...