中文摘要：

文章介绍了国际贸易中的同质和差异产品分类及其在国际贸易实证研究中的作用。Rauch（1999）按产品价格的公开程度将900多种SITC4位数产品分为三类：在有组织的商品交易所交易的同质产品、价格定期在某个专业贸易出版物上发布的产品和差异化产品。第一类产品所在市场接近于完全竞争,第三类接近于垄断竞争,第二类介于中间。三种产品的差异被广泛用于解决实证研究中的变量不可量度难题。文章用两个例子详细说明了Rauch分类的用处,一个是国际贸易中信息壁垒和贸易成本问题,一个是国内契约制度和比较优势问题。

英文摘要：

This paper introduces Rauch＇s classification of homogeneous and differentiated products in international trade and its application in empirical researches. Rauch （1999） classified more than 900 SITC 4-digit goods into three categories： homogeneous goods as products traded on organized exchanges, reference priced goods as those not traded on organized exchanges but possessing benchmark prices, and differentiated goods as those neither traded on organized exchanges nor possessing benchmark prices. The market of homogeneous goods is nearly in perfect competition, the market of differentiated goods is nearly in monopolistic competition, and the market of reference priced goods is in between. This classification is widely utilized to deal with the problem of unobservability in empirical researches as firm behaviors in different markets vary greatly. The paper illustrates how to use this classification with two examples： information barriers in international trade and domestic institution and comparative advantage.