【主讲】John Conley 教授（Vanderbilt University）
【主题】Dixit-Stiglitz approaches to interational trade: enough is enough
【时间】2012年3月16日（周五） 15：30－17：00
【地点】上海财经大学经济学院楼801室
【语言】 英文
【摘要】 We show that the Melitz (2003) continuum interpretation of the Dixit-Stiglitz monopolistic competition model does not represent a reasonable limit of a large finite economy unless it is built on a micro-foundation of heterogeneous agents. We argue for both theoretical and empirical reasons that each of these heterogeneous agents must choose consume at most a strictly bounded number of commodities instead of a strictly positive quantity of each of the infinite number of goods produced (as in Melitz). We show in a highly general framework that this implies that (1) the benefits to product diversity converge to zero as the economy gets large and (2) the proportion of imports goes to zero as countries get large in the presence of iceberg costs. We conclude it is difficult to build a case for trade exclusively on the back of a desire for product diversity. Instead, trade should take place when fixed costs are high relative to the size of the economies (and firm are therefore not price takers), different countries have fundamentally different production costs or different counties possess technology or resources that allow them to produce goods unavailable in other countries.
