Prepared for Annual Reviews of Economics.

This research examines theoretically and empirically the origins of agriculture. The theory highlights the role of climatic sequences as a fundamental determinant of both technological sophistication and population density in a hunter-gatherer regime. It argues that foragers facing volatile...

We establish that the debate between Eeckhout (2004; 2009) and Levy (2009) has still not resolved the key issue of whether the distribution of large US urban places in 2000 is consistent with a lognormal for the intire size range. We resolve this by introducing a new distribution function which...

In this paper, we link industry-level data on offshoring activities of U.S. multinational firms, import penetration, and export shares with individual level worker data from the Current Population Surveys. We examine whether increasing globalization through offshoring or trade has led to...

Critics of globalization claim that US manufacturing firms are being driven to shift employment abroad by the prospects of cheaper labor. Others argue that the availability of low-wage labor has allowed US-based firms to survive and even prosper. Yet evidence for either hypothesis, beyond...

Federal tax policy provides a broad array of incentives for energy investment. I review those policies and construct estimates of marginal effective tax rates for different energy capital investments as of 2007. Effective tax rates vary widely across investment classes. I then consider...

Recent studies in international trade report that new exporters often start selling small amounts and cease exporting in the first year. These findings reflect a substantial amount of uncertainty facing new exporters. In this paper we study whether export activities in the neighborhood reveal...

The empirical literature on economic growth and development has moved from the study of proximate determinants to the analysis of ever deeper, more fundamental factors, rooted in long-term history. A growing body of new empirical work focuses on the measurment and estimation of the effects of...

This paper presents concepts from economic analysis that shed light on the formation and breakup of sovereign states. First, we discuss the key trade-off between economies of scale in the provision of public good and political costs from heterogeneity of preferences. Second, we present four...

We examine the empirical relationship between the occurrence of inter-state conflicts and the degree of relatedness between countries, measured by genetic distance. We find that populations that are genetically closer are more prone to go to war with each other, even after controlling for...