Three aspects of efficiency measurement by data envelopment analysis are discussed here analytically. These aspects comprise output-specific input allocations by each firm, flexibility in the production process and the role of learning by doing in efficiency improvement.

This article focuses on productivity transitions from low to high levels of efficiency over time in the framework of the Farrell efficiency model. This transition probability approach is applied in two empirical applications in order to test the persistence of Farrell efficiency over time. The...

Methods of estimating efficiency by cost frontiers are analysed here by generalizing the efficiency distribution approach in Farrell's convex hull method of cost minimization.