Imperfect and Defective Outputs in Production Process: A DEA-Based Approach

In conventional DEA we assume that the outputs are produced completely and perfectly. However in real applications, there are systems which their produced outputs are possibly imperfect and defective. These outputs enter the system as inputs once again and after rebuilding, they will be completed. The present paper proposes a modification of the standard DEA model to incorporate such imperfect outputs. A mixed integer linear programming problem is proposed to deal with imperfect outputs