We study the robustness of empirical efficiency valuations of production processes in an extended Farrell model. Based on input and output data, an empirical efficiency status---efficient or inefficient---is assigned to each of the processes. This status may change if the data of the observed...

In this paper we deal with the measurement of technical efficiency (or X-efficiency) of institutions whose operations might be significantly affected by macroeconomic, environmental and non-controllable factors. For this purpose we introduce a four-stage DEA methodology based on the approach...