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...

Among the four largest cotton-producing countries, only Pakistan had not commercially adopted Bt cotton by 2010. However, the cultivation of first-generation (Cry1Ac) Bt cotton, unapproved and unregulated, increased rapidly after 2005. Using the propensity score matching method, this paper...

When analyzing bilateral trade flow data, zero trade flows are quite common and problematic when a gravity equation is estimated with a log-linear functional form. This has caused many researchers to either ignore the zero trade flows or to replace zero with a small positive number. Both of...

and this is a problem when estimating log-linear gravity equations. This has caused many researchers to either ignore the zero trade flows or to replace the zero with a small positive number. Both of these actions bias the resulting parameter estimates of the gravity equation. In this study we...