Ranking of decision-making units using data envelopment analysis by considering multiple time periods

Data Envelopment Analysis (DEA) is a technique for evaluating homogeneous decision-making units. In this method, the efficiency score for each unit is obtained by comparing the performance of each Decision-Making Unit (DMU) with the performance of the other units. This performance score can be used as a criterion for ranking units. In many cases, a significant number of units are efficient, and therefore, the efficiency of the classic DEA models cannot be a good criterion for accurate ranking of DMUs. In this study, a method for ranking DMUs using their efficiency is presented in several time periods, so that three types of production possibility sets are introduced. In the first type, for each time period, an independent production possibility set is defined, in the second type, a combination production possibility set is used for all time periods, and in the third type, a community production possibility set is created, which considers all time periods. Then, corresponding to each type, one efficiency number is obtained for each DMU. Therefore, the three values of efficiency resulting from the three methods are combined using the Shannon entropy method and define a general performance criterion for each unit. This criterion is ultimately considered as the main indicator for ranking units.