A NOVEL DEA APPROACH FOR EVALUATING SUSTAINABLE SUPPLY CHAINS WITH UNDESIRABLE FACTORS

In every production process, decreasing inputs consumption and increasing outputs production are of desired goals. There exist undesirable outputs in every production process which are by-products of the desirable outputs. Thus, the productions of desirable and undesirable outputs are dependent to each other. This means, productions of undesirable outputs are inevitable. In data envelopment analysis (DEA) literature, many papers considered undesirable outputs in analysis but possible dependencies between production of desirable and undesirable outputs have not been addressed. The aim of this paper is to consider the possible dependency between desirable and undesirable outputs. Then, a DEA model for evaluating a sustainable supply chain as well as each stage in the chains is presented. Some theorems are also provided to describe the model. A case study in a sustainable supply chain is also presented and the results are analysed.