A new approach for considering a dual-role factor in supplier selection problem: DEA with efficient and inefficient frontiers

This paper addresses the problem of a factor in supplier selection analysis which may be classified either an input or an output. The quantity of such a factor may influence the relative efficiency of the suppliers. Despite the fact that there are several publications addressing dual-role factors، it seems that their idea of classifying a factor as an input or an output within a single model cannot consider the causality relationships between inputs and outputs. A simple approach is proposed to resolve this limitation and to consider dual-role factor as well. A numerical example demonstrates the application of the proposed approach in supplier selection context.