Relationships among Labor, Bullock, and Tractor Inputs in Pakistan Agriculture
基于1987-88年巴基斯坦西北边境省两季调查数据，使用对偶方法和超越对数成本函数，估计拖拉机与人力、畜力之间的替代弹性，发现拖拉机可替代人力和畜力。
Abstract The purpose of this study is to examine relationships among different inputs on tractorized and non‐tractorized plots in the North West Frontier Province of Pakistan. The analysis is based on survey data for 1987–88 covering two seasons. A duality approach with a translog cost function is used to estimate cost and input shares. The estimated Allen elasticities of substitution, after correcting for sample selectivity bias, indicate that tractors are a substitute for human and animal labor. All the assumptions of the duality approach are fulfilled by the estimation procedure and the restrictions of theory are not rejected by the data.