Davoud Norouzi Bene - Department Of Applied Mathematics, Azarbaijan Shahid Madani University,Tabriz , Iran
Jafar Pourmahmoud - Department Of Applied Mathematics, Azarbaijan Shahid Madani University,Tabriz , Iran

Data Envelopment Analysis assumes that the values of inputs and outputs are exactly known. However, in most real-life problems, the exact values of the inputs and outputs are imprecise, one type of imprecise data is ordinal, In this paper, a new method for measuring the efficiency of units with ordinal data is presented and the results of this method are compared with Cooper method in this field , The results show that the efficiency scores obtained for inefficient units from the method presented in this paper are more realistic and reasonable than the results obtained from the Cooper's method.

Data Envelopment Analysis, Imprecise Data Envelopment Analysis, Ordinal Data, efficiency.