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...

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...

We propose a dynamic spatial theory to analyze the geographic impact of climate change. Agricultural and manufacturing firms locate on a hemisphere. Trade across locations is costly, firms innovate, and technology diffuses over space. Energy used in production leads to emissions that contribute...

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...

We study the relationship between geography and growth. To do so, we first develop a dynamic spatial growth theory with realistic geography. We characterize the model and its balanced growth path and propose a methodology to analyze equilibria with different levels of migration frictions. We...

This paper proposes a new method to measure ethnolinguistic diversity and offers new results linking such diversity with a range of political economy outcomes -- civil conflict, redistribution, economic growth and the provision of public goods. We use linguistic trees, describing the...

We investigate the empirical relationship between ethnicity and culture, defined as a vector of traits reflecting norms, attitudes and preferences. Using surveys of individual values in 76 countries, we find that ethnic identity is a significant predictor of cultural values, yet 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 organizations arise endogenously...

How does the formation of cross-country teams affect the organization of work and the structure of wages? To study this question we propose a theory of the assignment of heterogeneous agents into hierarchical teams, where less skilled agents specialize in production and more skilled agents...

We document several empirical regularities regarding the evolution of urban structure in the largest U.S. metropolitan areas over the period 1980-1990. These regularities relate to changes in resident population, employment, occupations, as well as the number and size of establishments in...