A Geometric Method in Data Envelopment Analysis to Obtain the Region of Efficiency

In this paper we consider a geometric method in one of the issues in data envelopment analysis to obtain the region of efficiency (RE) for a super efficient decision-making unit (DMU) especially when this region is concave. First, we identify production possibility set(PPS) and reduced production possibility set (RPPS o ). We determine region of efficiency and the region will be number of convex regions by applying this method. In this procedure, a super-efficient DMU o is connected to the most n adjacent DMUs on the efficient frontier of .Then we will use equations of faces of convex regions in the boundary of achieved region of efficiency. Finally examples are given for clarifying, this particular subject.