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 firm growth and exit rates decline with size? What determines the size distribution of firms? This paper presents a theory of firm dynamics that simultaneously rationalizes the basic facts on firm growth, exit, and size distributions. The theory emphasizes the accumulation of industry...

In this essay we review the empirical literature about sovereign debt and default. As we survey the work of economists, historians, and political scientists, we also emphasize parallel developments by theorists and recommend steps to improve the correspondence between theory and data.

Financial crises in emerging market countries appear to be very costly: both output and a host of partial welfare indicators decline dramatically. The magnitude of these costs is puzzling both from an accounting perspective -- factor usage does not decline as much as output, resulting in large...

The stock of sovereign debt is typically measured at face value. This is a misleading indicator when debts are issued with different contractual forms. In this paper we construct a new measure of the stock of external sovereign debt for 100 developing countries from 1979 to 2006 that is...

We develop a macroeconomic model with physical and human capital, human capital risk, and limited contract enforcement. We show analytically that young (high-return) households are the most exposed to human capital risk and are also the least insured. We document this risk-insurance pattern in...

Why is it difficult to restructure sovereign debt in a timely manner? In this paper we present a theory of the sovereign debt restructuring process in which delay arises as individual creditors hold-up a set- tlement in order to extract greater payments from the sovereign. We then use the theory...

We study the impact of intersectoral and interregional trade linkages in propagating disaggregated productivity changes to the rest of the economy. Using regional and industry data we obtain the aggregate, regional and sectoral elasticities of measured TFP, GDP, and employment to regional and...

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...

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...