Statistical Significance of Indicators of Efficiency and Incentives: Examples from West African Agriculture
利用西非小米和高粱生产的农场数据，分析贸易理论中的效率与激励指标（如国内资源成本系数和有效保护率）的分布特征，发现这些指标高度可变且偏斜，对价格参数敏感，若忽视变异性可能导致政策建议误导。
Abstract Indicators of efficiency and incentives derived from trade theory, such as the domestic resource cost coefficient (DRC) and effective protection (EP), are generally presented as simple means. Analysis of their distributions, using farm data on millet and sorghum production from West Africa, shows them to be highly variable and, in some cases, to be significantly skewed. The analysis also shows the indicators to be highly elastic to changes in such parameters as input and output prices. If this variability is not considered when making inferences from such data, policy recommendations can be seriously misleading because they are based on different farming populations.