自由贸易抑或贸易保护——国际贸易的经济增长效应再考察

全球经济复苏过程中,发达国家与新兴经济体之间关于自由贸易的争议也变得空前激烈。国际贸易是否有利于全球经济增长?这实际上是长期以来国际经济学与发展经济学领域颇具争议的问题之一,而在当下对这一问题进行重新审视更具有重要的现实意义。传统贸易理论对贸易合理性的探究尽管触及了经济增长问题,但在贸易静态收益理论的框架下,国际贸易究竟是否会促进一国经济增长,既取决于各个国家在各个发展阶段的经济增长究竟偏向于出口部门还是进口部门,也取决于各种贸易政策对各个部门的相对供给和相对需求的影响。本文对现有针对国际贸易与经济增长关系所做的实证研究作了系统回顾和分析总结,明确指出了目前各种看似矛盾的实证证据背后的理论和技术根源。在此基础上,运用两阶段最小二乘估计(2SLS)和GMM动态面板回归技术,对1960～2006年期间全球各国面板数据进行分析,对不同收入水平的国家组别分别就其贸易占GDP比重与GDP增长之间的关系进行实证检验。文章发现,上述实证研究证明国际贸易对经济增长的促进作用与一国经济发展阶段相关,但对不同收入水平的国家而言则存在差异,同时进口和出口在经济增长中的表现也存在差异性。总体来看,对中等收入国家而言,贸易占GDP比重与GDP增速之间的关系最强,进出口均有较强带动作用;高收入国家贸易占GDP比重与GDP增速之间关系较弱,进口的作用甚至大于出口;低收入国家贸易占GDP比重与GDP增速之间的关系最弱,进口甚至有抑制作用。

Free Trade or Trade Protectionism: A Resurvey on Economic Growth Effect in International Trade

In the process of economic recovery, debates about free trade between developed economies and emerging economies are becoming serious. Whether international trade is really good to global economic growth? This issue has been highly disputed in the fields of international economics and development economics for a long term, furthermore it calls more attention at this sensitive stage. While traditional trade theory verifying the rationality of free trade touchs on the facts of its growth effect, under the framework of static trade gains, the growth effect of international trade is not only depend on whether the growth leans to import sectors or to export sectors, but also influenced by the trade policy impacts on the relative supply and demand of various sectors. This paper makes a thorough review on the empirical studies related to the relationship between international trade and economic growth and clarifies the theoretical and technical reasons behind the apparent contradictionary facts. By using 2SLS and GMM estimation model, we analyze the panel data set covering periods of 1960~2006 and 86 countries. The analysis indicates that the relationship between economic growth and international trade is robust, various income group, however, perform differently. With regard to the relationship between share of trade and GDP growth rate, middle income countries have the strongest relationship, high income countries have moderate relationship and low income countries have relatively weak relationship. With respect to export and import, they are all significant for the middle income countries, export is less important than import for high income countries, import hinder the growth of low income countries and export also play trivial roles in their economic growth.