Measurement of technical and allocative efficiencies using a CES cost frontier: a benchmarking study of Japanese transmission-distribution electricity

This paper estimates the technical and allocative inefficiencies of the transmission-distribution sector of Japanese electric utilities using a panel data during the 1981-1998 period. A stochastic production frontier of the CES form is jointly estimated with input demand equations. Taking advantage of the self-duality, we retrieve the cost frontier by which the impacts of technical and allocative inefficiencies on costs and input demands are measured. The estimated elasticity of substitution is significantly different from unity in favor of the CES specification over the Cobb-Douglas. The results show that observed costs are 9 to 48% higher than the efficient level; technical inefficiency raises costs by 1 to 28%, while allocative inefficiency does so by 8 to 30%. Although their impacts on costs are similar, technical inefficiency more fluctuates so the differences in the performance of utilities are mainly due to technical inefficiency. We also find a substantial over-utilization of capital for all utilities.