Firms’ decisions about which goods to produce are often made at a more disaggregate level than the data observed by empirical researchers. When products differ according to production technique or the way in which they enter demand, this data aggregation problem introduces a bias into standard...

This article reviews the empirical evidence on firm heterogeneity in international trade. A first wave of empirical findings from microdata on plants and firms proposed challenges for existing models of international trade and inspired the development of new theories emphasizing firm...

This Paper presents a model of international trade that features heterogeneous firms, relative endowment differences across countries, and consumer taste for variety. The Paper demonstrates that firm reactions to trade liberalization generate endogenous Ricardian productivity responses at the...

This Paper develops a model of endogenous product selection by firms. The theory is motivated by new evidence we present on the importance of product switching by US manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than...

We develop a methodology for identifying departures from relative factor price equality across regions that is valid under general assumptions about production, markets and factors. Application of this methodology to the United States reveals substantial and increasing deviations in relative...

Since the mid-1990s, researchers have used micro datasets to study countries' production and trade at the firm level and have found that exporting firms differ substantially from firms that solely serve the domestic market. Across a wide range of countries and industries, exporting firms have...

Despite the fact that importing and exporting are extremely rare firm activities, economists generally devote little attention to the role of firms when discussing international trade. This paper summarizes key differences between trading and non-trading firms, demonstrates how these differences...

Relative wages vary considerably across regions of the United Kingdom, with skill-abundant regions exhibiting lower skill premia than skill-scarce regions. This Paper shows that the location of economic activity is correlated with the variation in relative wages. UK regions with low skill premia...