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, the anchor points in DEA, as an important subset of the set of extreme efficient points of the production possibility set (PPS), are studied. A basic definition, utilizing the multiplier DEA models, is given. Then, two theorems are proved which provide necessary and sufficient...