Summary

Models of comparative advantage in international trade explain specialization using differences in autarky relative prices. This literature has traditionally focused on the Heckscher–Ohlin and Ricardian models. The former emphasizes differences in factor abundance across countries and in factor intensity across goods; the latter focuses on relative productivity differences across countries and goods. However, unrealistic assumptions and stark assumptions have hindered empirical assessment of these models. Contemporary models now allow researchers to overcome these hurdles. New models of Ricardian comparative advantage incorporate realistic geography and multiple countries. Similar advances have freed the Heckscher–Ohlin model from some of its theoretical straightjackets. In addition, researchers have started to provide microfoundations for the Ricardian model and to formalize how institutions and factor market distortions might generate patterns of comparative advantage. Trade economists have also started to think about magnitudes in a different way; that is, through general equilibrium counterfactual experiments.