Casual empiricism suggests that additive trade costs, such as quotas, per-unit tariffs, and, in part, transportation costs, are prevalent. In spite of this, we have no broad and systematic evidence of the magnitude of these costs. We develop a new empirical framework for estimating additive...

In this paper, I survey the recent theoretical literature that incorporates heterogeneous labor into models of international trade. The models with heterogeneous labor have been used to study how talent dispersion can be a source of comparative advantage, how the opening of trade affects the...

We weigh into the debate about whether rising productivity is ever a consequence rather than a cause of exporting. Exporting and investing to raise productivity are complimentary activities. For lower-productivity firms, incurring the fixed costs of such investments is justifiable only if...

This paper reviews the literature on governments' motivations for negotiating and joining international trade agreements. I discuss both normative explanations for trade agreements and explanations based on political-economy concerns. Most of the paper focuses on the purpose of multilateral...

We use the 2018-2019 U.S. trade war to examine how supply chains adjustments to a tariff cost shock affect imports and exports. Using confidential firm-trade linked data, we show that the decline in imports of tariffed goods was driven by discontinuations of U.S. buyer-foreign supplier...

The U.S. opioid crisis is now driven by fentanyl, a powerful synthetic opioid that currently accounts for 90% of all opioid deaths. Fentanyl is smuggled from abroad, with little evidence on how this happens. We show that a substantial amount of fentanyl smuggling occurs via legal trade flows,...

We study the global innovation and diffusion of ideas by introducing trade into the model in Eaton and Kortum (1999) (EK). This extension allows us to use international trade flows and country-level factor costs to estimate both the intensity of innovation within countries over time and...