Directional Distance Functions (DDFs) are becoming a popular way of measuring efficiency as they encompass the Shephard output and input distance functions as special cases. However, the most critical and still unsolved issue related to DDF remains the selection of the direction along which to...

This study has two principal objectives. The first objective is to measure and compare the performance of European railways. The second objective is to illustrate the usefulness of econometric distance functions in the analysis of production in multioutput industries, where behavioural...