Agricultural Distortions in Sub-Saharan Africa: Trade and Welfare Indicators, 1961 to 2004
修改了贸易限制指数，精确衡量1961年以来19个非洲国家农业政策对生产者和消费者价格的扭曲效应，发现过去二十年政策改革显著，但该地区贸易和经济福利损失仍高于亚洲和拉丁美洲。
For decades, agricultural price and trade policies in Sub-Saharan Africa hampered farmers' contributions to economic growth and poverty reduction. This paper draws on a modification of so-called trade restrictiveness indexes to provide theoretically precise partial-equilibrium indicators of the trade and welfare effects of agricultural policy distortions to producer and consumer prices in 19 African countries since 1961. Annual time series estimates are provided not only by country but also, for the region, by commodity and by policy instrument. The findings reveal the considerable extent of policy reform over the past two decades, especially through reducing export taxation; but they also reveal that national policies continue to reduce trade and economic welfare much more in Sub-Saharan Africa than in Asia or Latin America.