Document Type : Research Paper
Department of Mathematics, Rasht Branch, Islamic Azad University, Rasht, Iran.
Department of Mathematics, Qazvin Branch, Islamic Azad University, Qazvin, Iran.
Department of Mathematics, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
In this paper using DEA technique, four-stage DEA model mooted in order to consider the situation in which returned products exist. Returned products are the inputs of the previous sub-processes that need to be reprocessed due to existence of flaws. Here, a supply chain with four stages as supplier, manufacture, distributor, and retailer with intermediate and return products has been considered and a DEA model formulated for performance analysis.