Preferential trade agreements and their role in world trade

This paper investigates the effects of preferential trade agreements (PTAs) on bilateral trade using a comprehensive data base of PTAs in force and a detailed matrix of world trade. Total trade between PTA partners is a poor proxy for preferential trade (trade in tariff lines where preferences are likely to matter): while the former was one-third of global trade in 2000-2002, the latter was between one-sixth and one-tenth. Gravity model estimates indicate that using total trade to assess the impacts of PTAs leads to a significant downward bias in the PTA coefficient: the semi-elasticity of trade with respect to PTA membership rises from 87% for total trade to 119% for preferential trade. Product exclusions and long phase-in periods significantly limit preferential trade; the marginal impact of South-South agreements on preferential trade is much higher than North-South PTAs, while the effect of North-North agreements is insignificantly different from zero.