Résumé
In this chapter, we aim to find a mathematical solution to compute the impact between two irrelevant decision matrices in a complex decision-making problem using multiple-criteria decision-making (MCDM) methods. The existing MCDM methods merely provide solutions for the one-stage decision-making procedure and do not take other effective variables outside of the decision matrix into account, while in real-world processes, the decisions always impact by the variables where they appear to be irrelevant. To demonstrate our proposed approach, it is applied to a case of supplier selection and firm’s strategies in which the interaction of selected strategies has been investigated on the selection of the best supplier. In order to handle the uncertainty that emerge during the process, this four-section approach is implemented as a grey framework and deals with grey Entropy, grey-TOPSIS, and the grey strategies interaction model. With comparison of rankings in computation with impact of selected strategies and without them, results indicated essentially the difference between these two cases.