This paper reviews the recent theoretical literature on heterogeneous firms and trade, which emphasizes firm selection into international markets and reallocations of resources across firms. We discuss the empirical challenges that motivated this research and its relationship to traditional...

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