Ranking Decision Making Units with Fuzzy Data Using Cross-efficiency with use of ranking function

Data covering analysis is a technique for evaluating the performance of homogeneous decision-making units. In evaluating the performance of units, it is necessary the efficiency and ranking of units be done (be calculated). Ranking decision-making units is based on efficiency. According to the existence of various efficacies in the applied examples, different techniques have been developed for ranking, that in this study, cross efficiency method has been used. This technique has been developed for fuzzy input and output modes. While data are fuzzy, cross efficiency table has been calculated inaccurately and table entries are fuzzy numbers, so the average (mean) of calculated efficiency in the table is also a fuzzy number. Since comparing the averages of obtained efficiencies ranks the decision-making units, it is necessary to propose a solution for this comparison. In this research, after providing the required grounds with assistance of models and doing the necessary changes in them, the averages of efficiency are compared by assistance of fuzzy ranking function. an‎d with the knowledge that every decision-making unit that has better average (mean) is more efficient, decision-making units are ranked.