Bank efficiency scores usually serve as a tool for comparing institutions with each other while allowing us to quantify sub-optimal decision-making unit choices. In the case of inter-country comparisons, such differences can also arise because of macro-economic heterogeneity between countries....

In response to a question raised by Knox Lovell, we develop a method for estimating directional output distance functions with endogenously determined direction vectors based on exogenous normalization constraints. This is reminiscent of the Russell measure proposed by Färe and Lovell (J Econ...