We show in a multi-sector, heterogeneous-firm trade model that the effect of tariffs on entry, especially in the presence of production linkages, can reverse the traditional positive optimal tariff argument. We then use a new tariff dataset, and apply it to a 189-country, 15-sector version of...

Three sources of gains from trade under monopolistic competition are: (i) new import varieties available to consumers; (ii) enhanced efficiency as more productive firms begin exporting and less productive firms exit; (iii) reduced markups charged by firms due to import competition. The first...

The purpose of this paper is to identify conditions under which hedonic price indexes provide an exact measure of consumer welfare, so that the welfare effects of quality change can be inferred. Our results are quite positive in providing a rational for existing practices, though the conditions...