NAFTA's and CUSFTA's Impact on International Trade
利用详细的贸易和关税数据，识别了优惠贸易协定对贸易量和价格的影响，发现NAFTA和CUSFTA显著增加了贸易量，但对价格和福利影响较小。
"This paper identifies the effects of preferential trade agreements on trade volumes and prices using detailed trade and tariff data. It identifies demand elasticities by developing a difference in differences based method that exploits the fact that the additional wedge driven between consumption patterns in a liberalizing versus a non-liberalizing country is directly related to the tariff reduction. Supply elasticities are identified by using tariffs as instruments for observed quantities. Analysis of world-wide trade data for 5,000 commodities shows that NAFTA and CUSFTA have had a substantial impact on international trade volumes, but a modest effect on prices and welfare. NAFTA and CUSFTA increased North American output and prices in many highly-protected sectors by driving out imports from non-member countries"--National Bureau of Economic Research web site.