1 Do Preferential Trade Agreements Increase Members ’ Agri-food Trade?

copies of this document for non-commercial purposes by any means, provided that this copyright notice appears on all such copies. 2 Do preferential trade agreements increase members ’ agri-food trade? This study estimates the effect of a diverse group of 30 PTAs on members ’ trade of 26 agri-food products categorized into eight commodity sectors for 1990, 1995, 2000 and 2000 using disaggregated trade data for 40 countries and the Heckman selection model. Results show that whether reported zero trade-flows are considered actual or potential affects the size of the estimated PTA impacts. However, irrespective of the true nature of the zero trade-flows, the effects of PTAs are found positive and statistically significant. OLS estimates fall between the Heckman-model-derived conditional and unconditional effects of PTAs