进口种类、产品质量与贸易福利:基于价格指数的研究

Variety,Quality and the Gains from Trade:An Analysis Based on the Price Index

本文基于中国1995-2014年的进口数据,通过构建嵌套Logit模型从种类和质量两个方面将传统价格指数修正为精确价格指数,进一步推导并估计产品质量,分析了进口贸易中的福利收益。研究发现:进口种类及产品质量对贸易福利的影响与传统价格指数的作用相反,进口种类多样化对中国贸易福利的改进呈波动上升趋势,20年间由于进口产品种类的增长,最终精确价格指数平均逐年向下调整约0.2%,累积下降约6%;中国消费者平均每年由于进口产品质量升级而获得的福利相当于GDP的1.24%,产品质量与进口种类改变带来大体等价的贸易福利,二者都是分析进口福利问题不可或缺的重要维度。

Based on China＇s import data from 1995 to 2014, this paper introduces a three-level nested Logit model for deriving the price index formula, in which the quality factor can be included. We show that the conventional price index makes an impact in the opposite way as how variety and quality do. The benefit of variety keeps increasing generally, although with some volatility. The average adjustment of the final ex- act price index is about 0. 2 percent every year and 6 percent cumulatively due to the increase of varieties in these 20 years. On average, China＇s consumers benefit 1.24% of GDP in terms of the quality upgrade. Furthermore, the changes in product quality and variety bring roughly equivalent welfare, which means that these two factors are both important dimensions affecting import welfare.