Two innovations in the last century have changed dramatically the cost of communicating and transmitting information: The first is the widespread adoption of telephony; the second is the internet. We study the implications of these changes in ICT for urban structure. We find robust evidence that...

Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a general equilibrium theory of economic growth in an urban...

Two innovations in the last century have changed dramatically the cost of communicating and transmitting information: The first is the widespread adoption of telephony; the second is the internet. We study the implications of these changes in ICT for urban structure. We find robust evidence that...

With average temperature ranging from -20°C at the North Pole to 30°C at the Equator and with global warming expected to reach 1.4°C to 4.5°C by the year 2100, it is clear that climate change will have vastly different effects across the globe. Given the abundance of land in northern...

We study the urban structure of the city of Detroit. Following several decades of decline, the city's current urban structure is clearly not optimal for its size, with a business district immediately surrounded by a ring of largely vacant neighborhoods. We propose a model with residential...

Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a theory of economic growth in an urban environment. We show that...

Urban growth refers to the process of growth and decline of economic agglomerations. The pattern of concentration of economic activity, and its evolution, has been found to be an important determinant, and in some cases the result, of urbanization, the structure of cities, the organization of...

Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a theory of economic growth in an urban environment. We show how...

We study empirically technology diffusion across countries and over time. We find significant evidence that technology diffuses slower to locations that are farther away from adoption leaders. This effect is stronger across rich countries and also when measuring distance along the south-north...

This paper proposes a simple theory of a system of cities that decomposes the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities, but also to greater frictions through...