Iranian Journal of Operations Research

en Hybrid model for evaluation of DMUs with principles of strong and weak disposability in the presence of grey undesirable factors Mathematical Modeling and Applications of OR Mathematical Modeling and Applications of OR پژوهشی Original In the evaluation of decision making units with classical models of data envelopment analysis, it is assumed that the factors are deterministic. In some decision-making problems, the amount of inputs or outputs of the units is not exactly known and it is a three-parameter interval in grey form. In this case, it is recommended to choose the factors from their center of gravity. In the classic models of data envelopment analysis, all factors are also considered desirable, but in real problems there are undesirable factors too which cannot be used to evaluate problems with undesirable inputs and undesirable outputs. In this paper, a model is presented for calculating the efficiency of decision making units in the presence of the center of gravity of undesirable three-parameter interval grey undesirable factors based on the combination of strong and weak disposability principles. To this end, the proposed method is discussed with a practical example.   Data Envelopment Analysis, Center of gravity, Efficiency, Strong and weak disposability. 32 46 http://iors.ir/journal/browse.php?a_code=A-10-1431-6&slc_lang=en&sid=1 jafar pourmahmoud pourmahmoud@azaruniv.ac.ir 00031947532846002778 00031947532846002778 Yes Azarbaijan Shahid Madani University, Department of Applied Mathematics, mahdi eini mahdi_eini@azaruniv.ac.ir 00031947532846002779 00031947532846002779 No Azarbaijan Shahid Madani University, Davood Darvishi Salokolaei d_darvishi@pnu.ac.ir 00031947532846002780 00031947532846002780 No Payame Noor University, Department of Mathematics Saeid Mehrabian saeid_mehrabian@khu.ac.ir 00031947532846002781 00031947532846002781 No Kharazmi University