基于改进的引力模型解析我国外贸发展的动因变化

The Analysis on the Change of Motivation in China′s Foreign Trade based on Improved Gravity Model

本文通过将Novy改进的引力模型进行分解,发现影响外贸发展的主要因素是经济的发展和贸易成本的下降,通过结合中国、印度和20个国家近15年的贸易和经济发展数据,验证了Novy理论的普适性;在此基础上,本文还将中国与20个国家在中国加入WTO前后和金融危机爆发前后的贸易变化进行经验分析,得到的基本结论是:加入WTO后贸易成本的贡献度明显上升(提升17%),说明加入WTO后良好的贸易环境和各种壁垒的下降确实降低了我国的贸易成本,但经济增长对外贸发展仍然起到至关重要的推动作用(提升了51%)。而金融危机爆发之后,贸易成本的增加是导致金融危机后我国外贸下滑的主要原因,虽然经济增长对外贸有正向的贡献,但贡献度较小(仅为13%),不能弥补贸易成本的负面影响。

In this paper,by decomposing the improved gravity model designed by Novy,it is found that economic development and the decline in trade cost are the main factors which affect the development of foreign trade.Meantime,the paper makes use of trade and economic development data of China,India and 20 economies in the past 15 years in order to verify the universality of the theory.Based on the above research,the paper will do empirical analysis about China and 20 economies during China′s WTO entry and financial crisis.The conclusion is that the contribution of trade cost is increased apparently(increase by 17%) after the accession to the WTO.This result indicates that trade cost is really reduced due to a good trading environment and the decline of various barriers to trade.However,economic growth still plays the critical role in promoting trade(increase by 51%).On the other hand,after the outbreak of the financial crisis,the increase in trade cost is the main reason which leads to decline in China′s foreign trade.Although the result demonstrates that economic growth has a positive contribution to foreign trade,the contribution is low(only 13%),which can not compensate for the negative impact of trade cost.