The Empirical Assessment of Technology Differences: Comparing the Comparable
基于事实和反事实替代弹性比较不同时空的技术，将估计的替代弹性差异分解为两个反事实成分，并以1970年代初石油危机前后资本对能源价格的弹性为例说明。
This paper compares technologies across space and time on the basis of factual and counterfactual substitution elasticities and argues that differences in estimated substitution elasticities should be decomposed into two counterfactual components. While the first component is designed to indicate how the ease of substitution is altered by varied economic circumstances, the second addresses the question of how technologies would compare under genuinely comparable situations. This argument is illustrated by the example of energy-price elasticities of capital before and after the oil crisis of the early 1970s.