Quantitative results from a large class of structural gravity models of international trade depend critically on the elasticity of trade with respect to trade frictions. We develop a new simulated method of moments estimator to estimate this elasticity from disaggregate price and trade-flow data...

This paper uses 68 measures of trade policy and trade liberalization to ask if membership in theWorld Trade Organization (WTO) and its predecessor the General Agreement on Tariffs and Trade (GATT) is associated with more liberal trade policy. Almost no measures of trade policy are significantly...

In light of the substantial movement towards trade liberalization during the postwar period, this paper attempts to determine if, and when, countries experienced statistically significant changes in the paths of their export-GDP and import-GDP ratios. We find that: (1) most trade ratios...

Casual empiricism suggests that additive trade costs, such as quotas, per-unit tariffs, and, in part, transportation costs, are prevalent. In spite of this, we have no broad and systematic evidence of the magnitude of these costs. We develop a new empirical framework for estimating additive...

In this paper, I survey the recent theoretical literature that incorporates heterogeneous labor into models of international trade. The models with heterogeneous labor have been used to study how talent dispersion can be a source of comparative advantage, how the opening of trade affects the...

This chapter (to appear in the forthcoming Handbook of International Economics, Vol. 5) develops a framework with which to interpret and survey answers to the question: how does increased openness affect aggregate welfare in a typical developing country? We decompose answers into four...

We introduce quality differentiation and an extensive margin of products into a standard quantitative, general equilibrium model of international trade. Both the quality and the quantity of a product play a role in its contribution both to consumption and to production. The framework allows...

This paper reviews a new framework for analyzing the interrelationship between inequality, unemployment, labor market frictions, and foreign trade. This framework emphasizes firm heterogeneity and search and matching frictions in labor markets. It implies that the opening of trade may raise...

Three sources of gains from trade under monopolistic competition are: (i) new import varieties available to consumers; (ii) enhanced efficiency as more productive firms begin exporting and less productive firms exit; (iii) reduced markups charged by firms due to import competition. The first...