We develop a method for identifying departures from relative factor price equality that is robust to unobserved variation in factor productivity. We implement this method using data on the relative wage bills of non-production and production workers across 170 local labor markets comprising the...

This paper examines the frequency, pervasiveness and determinants of product switching among U.S. manufacturing firms. We find that two-thirds of firms alter their mix of five-digit SIC products every five years, that one-third of the increase in real U.S. manufacturing shipments between 1972...

This paper develops a general equilibrium model of multi-product firms and analyzes their behavior during trade liberalization. Firm productivity in a given product is modeled as a combination of firm-level quot;abilityquot; and firm-product-level quot;expertisequot;, both of which are...

This paper examines the frequency, pervasiveness and determinants of product switching among U.S. manufacturing firms. We find that two-thirds of firms alter their mix of five-digit SIC products every five years, that one-third of the increase in real U.S. manufacturing shipments between 1972...

Standard models of international trade devote little attention to firms. Yet of the 5.5 million firms operating in the United States in 2000, just 4 percent engaged in exporting, and the top 10 percent of these exporting firms accounted for 96 percent of U.S. exports. Since the mid 1990s, a...

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 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 U.S. manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than...

This paper examines the determinants of intra-firm trade in U.S. imports using detailed country-product data. We create a new measure of product contractibility based on the degree of intermediation in international trade for the product. We find important roles for the interaction of country...

We combine data on individual trade transactions from U.S. customs records with comprehensive information on firms' employment from the Census Bureau's business register to examine wholesalers and retailers in U.S. exports and imports. Exporters and importers with 100 percent employment in...

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...