收益递增、运输成本与贸易模式

Increasing Returns,Transportation Costs and Patterns of Trade

本文建立一个两国模型，研究存在运输成本和收益递增场合贸易的模式与利得分配，探讨成本递减作为贸易保护理由的条件，拓广Ethier（1982a）的分析。模型中制成品的生产可选用现代技术或传统技术，前者带来规模收益递增。基本结论是：模型参数及初始条件决定贸易均衡的类型以及贸易利益的得失。若收益递增越强、运输成本越低、制成品支出份额越高或相对经济规模越大则越容易形成专业化的生产与贸易格局，且专业化的格局类似于李嘉图模式（无运输成本、收益不变）的分析，即各国出口其具有比较优势的产品；出口收益递增产品的一方总是从贸易中获利，另一方可能获利也可能受损。建议政府大力扶持收益递增产业，积极推动工艺创新。

This paper extends Ethier（1982a） by taking transportation costs into account and assuming manufacturing goods can be produced with the cottage technology under constant returns to scale, or with the modern technology using differentiated intermediate goods under increasing returns to scale. Under such a context it is shown that different initial conditions determine different equilibria： strong increasing returns to scale, large relative economic scale, high expenditure share on manufacturing goods and low transportation costs are conducive to the formation of specialization. A country always gains from trade if it exports goods produced with modern technology, otherwise it may lose. It is recommended that governments should encourage the development of increasing-return industry and promote process innovation.