The monopolistic competition model in international trade offers three sources of gains from trade that do not arise in competitive models: expansion in product variety; a pro-competitive reduction in the markups charged by firms; and the self-selection of more efficient firms into exporting. Recent literature on trade with heterogeneous firms has emphasized the third of these effects, and the first two effects are ruled out when using a Pareto distribution for productivity with a support that is unbounded above. The goal of this paper is to restore a role for product variety and pro-competitive gains from trade by using a bounded Pareto distribution for productivity.

An examination of the methods to measure the product variety of imports and the gains from trade due to product variety. The application of the monopolistic competition model to international trade by Elhanan Helpman, Paul Krugman, and Kelvin Lancaster was one of the great achievements of international trade theory in the 1970s and 1980s. Monopolistic competition models have required new empirical methods to implement their theoretical insights, however, and in this book Robert Feenstra describes methods that have been developed to measure the product variety of imports and the gains from trade that are due to product variety. Feenstra first considers the consumer benefits from having access to new import varieties of differentiated products, and examines a recent method to estimate the elasticity of substitution (the extent of differentiation across products) and to use that information to construct the gains from import variety. He then examines claims of producer benefit from export variety, arguing that the self-selection of the more productive firms (as the low-productivity firms exit the market) can be interpreted as a gain from product variety. He makes use of a measurement of product variety known as the extensive margin of exports and imports. Finally, he considers an alternative approach to quantifying the gains due to product variety by comparing real GDP calculated with and without the extensive margin of trade.

The Melitz model highlights the importance of the extensive margin (the number of firms exporting) for trade flows. Using the World Bank’s Exporter Dynamics Database (EDD) featuring firm-level exports from 50 countries, we find that around 50 percent of variation in exports is along the extensive margin—a quantitative victory for the Melitz framework. The remaining 50 percent on the intensive margin (exports per exporting firm) contradicts a special case of Melitz with Pareto-distributed firm productivity, which has become a tractable benchmark. This benchmark model predicts that, conditional on the fixed costs of exporting, all variation in exports across trading partners should occur on the extensive margin. We find that moving from a Pareto to a lognormal distribution allows the Melitz model to match the role of the intensive margin in the EDD. We use likelihood methods and the EDD to estimate a generalized Melitz model with a joint lognormal distribution for firm-level productivity, fixed costs and demand shifters, and use “exact hat algebra” to quantify the effects of a decline in trade costs on trade flows and welfare in the estimated model. The welfare effects turn out to be quite close to those in the standard Melitz-Pareto model when we choose the Pareto shape parameter to fit the average trade elasticity implied by our estimated Melitz-lognormal model, although there are significant differences regarding the effects on trade flows.

Trade is a cornerstone concept in economics worldwide. This updated second edition of the essential graduate textbook in international trade brings readers to the forefront of knowledge in the field and prepares students to undertake their own research. In Advanced International Trade, Robert Feenstra integrates the most current theoretical approaches with empirical evidence, and these materials are supplemented in each chapter by theoretical and empirical exercises. Feenstra explores a wealth of material, such as the Ricardian and Heckscher-Ohlin models, extensions to many goods and factors, and the role of tariffs, quotas, and other trade policies. He examines imperfect competition, offshoring, political economy, multinationals, endogenous growth, the gravity equation, and the organization of the firm in international trade. Feenstra also includes a new chapter on monopolistic competition with heterogeneous firms, with many applications of that model. In addition to known results, the book looks at some particularly important unpublished results by various authors. Two appendices draw on index numbers and discrete choice models to describe methods applicable to research problems in international trade. Completely revised with the latest developments and brand-new materials, Advanced International Trade is a classic textbook that will be used widely by students and practitioners of economics for a long time to come. Updated second edition of the essential graduate textbook Current approaches and a new chapter on monopolistic competition with heterogeneous firms Supplementary materials in each chapter Theoretical and empirical exercises Two appendices describe methods for international trade research

International trade has grown rapidly over the past half century, accommodated by the transportation industry through concomitant growth and technological change. But while the connection between transport and trade flows is clear, the academic literature often looks at these two issues separately. This Handbook is unique in pulling together the key insights of each field while highlighting what we know about their intersection and ideas for future research in this relatively unexamined but growing area of study.

Thirty years after the region embarked on large-scale liberalization, trade policy could have been expected to become all but irrelevant. Instead, a mismatch between expectations and what could realistically be delivered set the stage for much of the disappointment, skepticism, and fatigue regarding trade policy in the region, particularly in the early 2000s. By setting the bar unrealistically high, governments and analysts made trade policies an easy target for special interests that were hurt by liberalization and for those ideologically opposed to free trade. The most immediate victims were the more tangible growth and welfare gains, whose relevance was lost amid the noise of grandiose visions.

This paper presents a simple model of monopolistic competition that features a general class of additively separable preferences without any fixed costs. While trade always crowds out less productive firms as long as countries are symmetric, we show that the impact is independent of entry/exit a la Hopenhayn, and is different from the effect of market size expansion, which may crowd in less productive firms. Our analysis pin-points the source of gains from trade in the presence of heterogeneous firms as bringing about new varieties from foreign countries by expanding more productive firms at home.