We document and then develop a model explaining and relating changes in firms’ organization and in urban structure. Sharing of business services by headquarters and of sector-specific intermediates by production plants within a city reduces costs, while congestion increases with city size. A...

This paper analyses a model of economic development in which international inequalities in the location of industry and income are supported by the agglomeration of industry in a subset of countries. Economic development may not be a gradual process of convergence by all countries, but instead...

This paper describes the spread of industry from country to country as a region grows. All industrial sectors are initially agglomerated in one country, tied together by input-output links between firms. Growth expands industry more than other sectors, bidding up wages in the country in which...

Why are some cities specialized and others diversified? What are the advantages and disadvantages of urban specialization and diversity? To what extent does the structure of cities, and the activities of firms and people in them, change over time? How does the sectoral composition of cities...

Why are some cities specialized and others diversified? What are the advantages and disadvantages of urban specialization and diversity? To what extent does the structure of cities, and the activities of firms and people in them, change over time? How does the sectoral composition of cities...

The incremental innovations that underlie much of modern economic growth typically involve changes to one or more components of a complex product. This creates a tension. On the one hand, a principal would like an agent to contribute innovative components. On the other hand, ironing out...