Urban diversity and economic growth

This paper considers the heterogeneity and diversity of cities as sources of economic growth. It links modern notions of economic growth to the distinguishing characteristics of cities and to the external effects on consumption and production produced by the internal diversity of urban areas. The paper reviews the role of traditional scale economies as well as the importance of diversity in economizing on shared inputs and transactions costs, and efficiencies arising from the operation of the law of large numbers in metropolitan areas. The authors also review recent empirical evidence on the importance of these elements of heterogeneity in conditioning economic growth.