Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Standard techniques used to estimate gravity equations, rely on bilateral variation to identify the effect of trade barriers on bilateral trade flows. In this paper, I develop a method that estimates the effects of country‐level variables on trade between countries in the presence of firm heterogeneity and country selection into trade, a natural extension of existing empirical models of international trade. I implement the method in services data, where available measures of trade policy provide information on the average level of regulations restricting entry into a country. The results suggest that policy barriers are important determinants of services trade flows.