Iranian Journal of Operations Research

other Inverse Data Envelopment Analysis on the Base of Non-Convex Cost Efficiency Mathematical Modeling and Applications of OR Mathematical Modeling and Applications of OR پژوهشی Original Cost efficiency in which cost coefficients are given for some inputs (cost coefficients can be different for disparate decision-making units (DMUs)) is one of the most important concepts in data envelopment analysis (DEA) to analyze the performance. Moreover, in some occasions, the cost performance and changes of input measures should be addressed while the convexity property is violated. Therefore, in this paper, first a DEA model is provided to assess cost efficiency based on the free disposal hull (FDH) model. Then, by considering cost and technical efficiencies achieved, a multi-objective problem called the inverse FDH cost model is presented to determine input values based on output changes while the cost and technical efficiency levels are preserved. The multi-objective problem is computed applying two approaches. Also, a dataset from the literature is presented to show the performance of the proposed method. For this purpose, we used the data of six banks in different countries. We added 2% to the outputs and analyzed the inputs with two models. In the first model, we used cost coefficients for weights, and in the second model, we used the same weights. Contrary to forecasts, some entries have decreased and others have increased. But from the results, we have noticed that the first model is more realistic because most of the solutions have increased in this model.   Cost efficiency, DEA, Inverse DEA, FDH. 135 148 http://iors.ir/journal/browse.php?a_code=A-10-1422-62&slc_lang=other&sid=1 Farzaneh Asadi Farzaneh Asadi farzaneh.asadi.fa@gmail.com 1111111111 1111111111 No Department of Industrial Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Department of Industrial Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Sohrab Kordrostami Sohrab Kordrostami sohrabkordrostami@gmail.com 1111111111 1111111111 Yes Department of Mathematics, Lahijan Branch, Islamic Azad University, Lahijan, Iran Department of Mathematics, Lahijan Branch, Islamic Azad University, Lahijan, Iran Alireza Amirteimoori Alireza Amirteimoori ateimoori@iaurasht.ac.ir 1111111111 1111111111 No Department of Applied Mathematics, Rasht Branch, Islamic Azad University, Rasht, Iran Department of Applied Mathematics, Rasht Branch, Islamic Azad University, Rasht, Iran Morteza Bazrafshan Morteza Bazrafshan bazrafshan@liau.ac.ir 1111111111 1111111111 No Department of Industrial Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran Department of Industrial Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran