en تخصصي Special پژوهشي Research <span style="font-size:11.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">Data Envelopment Analysis (DEA) is a non-parametric method for efficiency measurement. In the most common DEA models the method selects the most favorable weight set for all units in order to maximize their efficiency scores. The so called optimistic assessment determines the best efficiency score.&nbsp; To make the performance of DMUs more actionable, the evaluation can be addressed from pessimistic perspective. Under the optimistic and pessimistic points of view, the performance of a unit is assessed with two different evaluation methods. As a result, a different set of weights is achieved for each unit. Hence, to have a more realistic results and better discrimination among DMUs, a more applicable method of a common set of weights (CSW) is suggested. The contribution of the paper is three folded. (1) The proposed approach develops the weight restriction approach, taking into account both optimistic and pessimistic points of view, simultaneously. (2) The proposed weight restriction method considering double frontier generates a positive and a dissimilar set of weights. (3) With the achieved common set of weights the efficiency scores are calculated then the units are ranked. To highlight the details of the proposed method, a real world data application consists of real case study confirm that the presented procedure results in a more realistic and the comprehensive assessment. It also shows the superiority of the proposed method considering double frontier.</span></span></span> Data Envelopment Analysis, Common Set of Weights, Weight Restriction, Optimistic and Pessimistic Efficiencies, Double Frontier, Weight Dissimilarity 45 57 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-529-2&slc_lang=en&sid=1 A. Pourhabib Yekta apourhabibyekta@yahoo.com 10031947532846001740 10031947532846001740 Yes Department of Mathematics, Islamic Azad University, Sowmesara Branch, Guilan, Iran, M. Maghbouli mmaghbouli@gmail.com 10031947532846001741 10031947532846001741 No Department of Mathematics, Aras Branch, Islamic Azad University, Jolfa, Iran M. Mirzaei Chalakei Mohsenmirzaee37@yahoo.com 10031947532846001742 10031947532846001742 No Department of Mathematics, Islamic Azad University, Astaneh Ashrafieh Branch, Guilan, Iran