Quality differentiation, comparative advantage, and international specialization across products
将质量差异化引入李嘉图贸易模型，解释了工业化国家为何能生产各类产品而发展中国家专攻简单产品，并揭示了质量差异化如何影响发展中国家的贸易收益。
This paper introduces quality differentiation into a Ricardian model of international trade following Costinot (2009a). It shows (1) how quality differentiation can help industrialized countries to be active across the full board of products, complex and simple ones, while developing countries systematically specialize in simple products, in line with novel stylized facts. (2) Quality differentiation may thus help to explain why richer countries tend to be more diversified and why, increasingly over time, rich and poor countries tend to export the same products. (3) The analysis reveals a novel supply-side channel through which quality differentiation can increase the gains from inter-product (industry) trade for developing countries relative to industrialized countries.