When there are costs of trade, such as transport or other costs, the pattern of trade may not be well described by the usual measures of comparative advantage, which simply compare a country's costs or autarky prices to those of the world. Instead, a better comparison takes into account the...

The question here is whether the dynamic effects of opening to trade will increase or decrease comparative advantage. When comparative advantage is based on the abundance or scarcity of something that is costly to acquire, one expects rational behavior to respond to a change in prices by...

"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 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...