Commercial Policy in a “Fragmented” World
分析生产碎片化对商业政策的影响，关注最终品与中间品关税的相互作用以及垂直关系中的契约问题，对研究贸易政策与全球价值链的学者有参考价值。
There is abundant evidence that the production process of firms is becoming increasingly fragmented internationally, in the sense that a final manufactured good will consist of parts that have been manufactured in a variety of different countries. Studies of manufacturing industries suggest that the share of imported inputs in international trade rose significantly in the 1970's and 1980's, and that the fragmentation of the production process has been particularly pronounced in industries such as transportation equipment and electrical machinery.1 What difference does it make if trade reflects a fragmentation of the production process, rather than the traditional horizontal specialization in final goods? In this paper I focus on the implications of fragmentation for the analysis of commercial policy and emphasize two features of vertical relationships.2 The first is the market linkages that are introduced in models of fragmentation due to the interaction between tariffs on final goods and tariffs on intermediate goods. The incentives of countries regarding tariff reduction can vary significantly depending on the pattern of trade. The second feature of vertical specialization is that producers of final goods often require inputs that are specialized to their particular needs, so that vertical relationships may create contracting problems because of the possibility for opportunistic behavior. Commercial policy may play a role in altering the form of these vertical relationships.