presentation of a two stages method to determine the suitable benchmark and return to scale (case study: girls high school of one zone shiraz city)

In this paper, a two stages method to determine suitable benchmark and return scale of the decision making units set is presented. At first, all of the efficient reference set in no radial data envelopment analysis (DEA) based on linear programming is found. first, RAM model is introduced and units is investigated using this model, then, to run the given algorithm below steps is performed. At the first step, the type of reference set is introduced and at the second step, a unique linear programming problem based on primal dual method is proposed to know all of the possible reference sets for a decision making unit. At the third step, return to scale in the no radial DEA method is measured. Ultimately, girls high school of shiraz city one zone efficiency is investigated to show to be applicate of this method and suitable benchmark and return scale is presented for this set of decision making units.