This paper provides the first empirical analysis directly comparing the effects of customs unions (CUs) and free-trade agreements (FTAs) on members’ bilateral trade, while addressing the biases arising from loglinearization of the gravity model and crucial time-invariant unobservables. Since Fiorentino et al. (2007) question the popularity of CUs relative to FTAs, considering the latter to be more practical in the current trading climate, such a comparison seems especially relevant. While Baier and Bergstrand (2007) find an FTA to approximately double members’ bilateral trade after 10 years, the results of this paper find CUs to have had a much larger impact than FTAs
