Evaluating group performance of decision-making units (DMUs) is an application of data envelopment analysis (DEA) and usually provides a measure to compare the frontiers of the production possibility sets (PPSs) corresponding to different groups and the internal inefficiencies of DMUs associated...

In this paper we propose a method for finding the reference set of a decision making unit (DMU), without chasing down all alternative optimal solutions of the envelopment form, which is a strong degenerate problem. The reference set is useful as a benchmark for an inefficient DMU, for...