Heterogeneous workers, trade, and migration
研究了工人和企业在技能类型上的双向异质性如何影响贸易与移民的福利效应，发现贸易自由化虽加剧不平等但提高总体福利，而劳动力市场一体化通过降低工资压价和商品价格提升两国福利。
We analyze the welfare effects of trade and migration, focusing on two-sided horizontal heterogeneity among workers and firms. Horizontal (skill-type) heterogeneity among workers generates monopsonistic labor markets as well as within-firm wage inequality and an endogenous quality of worker–firm matches. In a model combining horizontal worker heterogeneity with monopolistic competition on goods markets, trade liberalization causes firm exit which raises wage markdowns and worsens the average quality of worker–firm matches. It also increases the degree of income inequality. Yet, aggregate welfare is higher under free trade than under autarky. Integration of labor markets leads to two-way migration between symmetric countries. Liberalizing migration has an ambiguous effect on the quality of worker–firm matches and income inequality, but it leads to lower wage markdowns and lower goods prices and thus to higher welfare in both countries. Our model advocates opening up labor markets simultaneously with trade liberalization.