S.E Esfidani - Department of Mathematics, South Tehran Branch, Islamic Azad University, Tehran, Iran
F Hosseinzadeh Lotfi - Department of Mathematics, South Tehran Branch, Islamic Azad University, Tehran, Iran

Traditional Data envelopment analysis (DEA) is a non-parametric approach thatmeasures the efficiency of comparable black box systems. There is a weakness in traditional DEAthat does not survey the internal structure of systems. Hence, for evaluating the efficiency of thesystems with interior structure, Network DEA(NDEA) was introduced. Two-stage systems are aspecial case of network systems. Several approaches were developed for measuring the efficiencyof these systems such as slacks-based measure approach. In this paper, we consider two-stagesystems with shared inputs between stages and final output in stage 1 and we shall suggest the noncooperativemodels for measuring the efficiency of these systems based on slacks-based measureapproach. Then, we shall calculate the overall efficiency of these systems as the product of theefficiency scores of the two stages. Finally, an illustrative example has been presented.

Data envelopment analysis, Efficiency, Two stage system, Non-cooperative, Slacks - based measure