Is the variation in bilateral trade flows across countries primarily due to differences in the number of exporting firms (the extensive margin) or in the average size of an exporter (the intensive margin)? And how does this affect the estimation and quantitative implications of the Melitz (2003)...

The Melitz model highlights the importance of the extensive margin (the number of firms exporting) for trade flows. Using the World Bank's Exporter Dynamics Database (EDD) featuring firm-level exports from 50 countries, we find that around 50% of variation in exports is along the extensive...

This note develops a framework for thinking about the following question: What is the maximum amount of consumption that a utilitarian welfare function would be willing to trade off to avoid the deaths associated with the pandemic? The answer depends crucially on the mortality rate associated...

We explore the implications of models with increasing returns, endogenous variety and firm-level heterogeneity for the quantification of the gains from trade. We first focus on the impact of trade liberalization on imported variety by analyzing the experience of Costa Rica from 1986 to 1992. We...

We introduce an instrumental variables approach to estimate the importance of unmeasured quality growth for a set of 66 durable consumer goods. Our instrument is based on predicting which of these 66 goods will display rapid quality growth. Using pooled cross- relatively sections of households...

Growth has fallen in the U.S., while firm concentration and profits have risen. Meanwhile, labor's share of national income is down, mostly due to the rising market share of low labor share firms. We propose a theory for these trends in which the driving force is falling firm-level costs of...

In the wake of the U.S.-Canada Free Trade Agreement, both the U.S. and Canada experienced a sustained increase in job reallocation, including firms moving into exporting. The change involved big firms as much as small firms. To mimic these patterns,we formulate a model of innovation by both...

Recent work highlights a falling entry rate of new firms and a rising market share of large firms in the United States. To understand how these changing firm demographics have affected growth, we decompose productivity growth into the firms doing the innovating. We trace how much each firm...

Externalities play a central role in most theories of economic growth. We argue that international externalities, in particular, are essential for explaining a number of empirical regularities about growth and development. Foremost among these is that many countries appear to share a common long...