Z-number based Improved Sustainability Index for the Selection of Suitable Suppliers

Information reliability is an important trait of effective decision-making. The practice of choosing suppliers in a sustainable environment has become popular recently. The organizations evaluate suppliers’ performance under economic, social, and environmental criteria. Generally, expert opinions are collected considering these criteria to select suitable suppliers. However, these opinions contain uncertainties due to the subjectiveness and impreciseness involved. Further, the information (collected from the experts) unreliability also adds to uncertainties in the supplier selection process. Z-number is a bimodal information system capable of modelling both uncertainty and reliability of expert opinions. The existing literature on sustainable supplier selection does not effectively utilize the Z-numbers and their information content. This work proposes a Z-number-based improved sustainability index to select suitable suppliers with enhanced utilization of the information. Further, the study provides a case study and comparative analysis to support the proposal.