The impact of EU trade preferences on the extensive and intensive margins of agricultural and food products
研究了1990-2006年间欧盟优惠贸易协定对发展中国家农产品和食品贸易的创造效应，发现协定主要通过扩展边际（增加产品种类）促进农产品贸易，但对加工食品无显著影响；集约边际（增加现有产品贸易量）仅受关税影响。
Abstract In this article, we study the trade creation effects of EU preferential trade agreements (PTAs) in the agriculture and food sectors for a large sample of developing countries in the period 1990–2006. We investigate the extent to which the PTAs affect trade through the extensive margin—number of exported products—or the intensive margin—volume of existing products. We use a gravity framework in a panel data setting, and different estimators to deal with the issues of zero trade flows and the presence of an upper bound in the dependent variable. The results show that EU PTAs positively affect the extensive margin in agricultural trade, but not in processed foods. As regards the intensive margin, the effect is driven by the role of tariffs alone, whereas the other provisions of PTAs do not exert any other significant impact on agricultural or food products.