U.S. county data for the last 20 or 30 years show that manufacturing employment has been deconcentrating. In contrast, the service sector exhibits concentration in counties with intermediate levels of employment. This paper presents a theory where local sectoral growth is driven by technological...

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...

Why do firms decide to offshore certain parts of their production process? What qualifies certain countries as particularly attractive locations to offshore? In this paper we address these questions with a theory of international production hierarchies in which teams arise endogenously to make...

Why do firm growth and exit rates decline with size? What determines the size distribution of firms and plants? This paper addresses these questions in a dynamic model of firm size with entry and exit that emphasizes the accumulation of specific factors in response to industry specific...

For centuries, most international trade involved an exchange of complete goods. But, with recent improvements in transportation and communications technology, it increasingly entails different countries adding value to global supply chains, or what might be called "trade in tasks." We propose a...

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 present a theory of spatial development. Manufacturing and services firms located in a continuous geographic area choose each period how much to innovate. Firms trade subject to transport costs and technology diffuses spatially across locations. The result is a spatial endogenous growth...

We use a simplified version of Garicano and Rossi-Hansberg (2005) to understand the impact of improvements in communications technology at the turn of the twentieth century on wages and organization. Improvements in communication technology allow individuals of different skills to abandon...