The Estimation of X-Inefficiency in Eighteen Countries
假设低收入国家的替代机制趋于失效，导致其投入产出关系主要由X-低效率解释，而高收入国家则反映要素价格。基于十八国普查数据的实证结果支持这一假设。
We hypothesize that the substitution mechanism tends to break down in low income countries. As a result the input-output relationship in low income countries is largely explained by their X-inefficiency, while the same relationship in high income countries generally reflects their factor prices. This hypothesis is consistent with the empirical results calculated from Census data for eighteen countries at various stages of development.