S. Sadri - Department of Mathematics, Karaj Branch, Islamic Azad University, Karaj, Iran
M. Rostamy Malkhalifeh - Department of Mathematics, Science and Research Branch, Islamic Azad University, Tehran, ‎Iran‎.
N. Shoja - Department of Mathematics, Firuozkooh Branch, Islamic Azad University, Firuozkooh, Iran

Undesirable Output such as pollution and waste may occasionally occur in the production process, which should be reduced to improve efficiency. In the present study, cost efficiency model is presented in the presence of undesirable output by Inverse Linear Programming, and the desirable cost is calculated in order to achieve cost efficiency for units that are technically efficient but not cost-‎efficient.‎

Data Envelopment Analysis, Undesirable Output, cost efficiency, Inverse linear programming