A Payan - Department of Mathematics, Islamic Azad University, Zahedan, Iran
F Khakzad - Department of Mathematics, Science &Research Branch, Islamic Azad University, Tehran, Iran

Different methods have been proposed for ranking efficient DMUs. One of these methods is using common set of weights. Liu et al.(computers & operations research, 35 (2008) 1624-1637) presented a method for obtain common set of weights and ranked efficient units using them. The aim of this paper is point out certain shortcoming in this work and giving ways which validate this method