Trade growth, the extensive margin, and vertical specialization




Mostashari, Shalah

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This dissertation consists of three essays in International Trade. The first essay studies the impact of changing tariffs on the range of goods countries export to the United States. The empirical analysis shows that tariffs tend to have a statistically significant but small impact: at best 5 percent of the increasing extensive margin for 1989-1999 and 12 percent for 1996-2006 is explained by tariff reductions. This suggests the extensive margin has not amplified the impact of tariffs on trade flows to such an extent that the relatively moderate tariff reductions since WW II can explain the strong growth of world trade. The second essay investigates the sector and country determinants of the range of goods that countries export to the United States. Besides relating the traditional determinants of comparative advantage, sectors’ factor intensities interacted with countries’ factor abundance to the extensive margin in a sector, the empirical investigation includes interactions between sector-level measures of intermediate intensity and trade frictions. Consistent with hypotheses about fragmentation, the results show that closer countries and countries with lower tariffs imposed on them export a wider range of goods in sectors that have large intermediate cost shares. The impact of trade frictions is, however, far less pronounced for the more skilled-labor intensive sectors that are characterized by use of a greater range of intermediates. The third essay studies the impact of trade liberalizations on U.S. bilateral trade from 1989-2001 with a focus on the influence of exporting country liberalizations which matter when exports are produced with imported intermediates. Guided by extensions of the Eaton and Kortum (2002) model which allows for production to involve the use of imported intermediates, the essay estimates a structural equation that links U.S. bilateral trade flows to both intermediate tariffs imposed by countries exporting to the United States and U.S. tariffs. The empirical estimates suggest that especially for less developed countries their own liberalizations have been quantitatively much more important in explaining bilateral trade growth with an effect 3 times larger than the impact of U.S. liberalizations.




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