Sustainable Supplier Evaluation in an Automotive Company Using Fuzzy Multi-Criteria Decision-Making Methods

Abstract

Sustainable supplier management literature is mainly on sustainable supplier selection but sustainable supplier performance monitoring & evaluation studies are scarce. Furthermore, the studies do not differentiate the sustainability evaluation criteria between the supplier selection and monitoring & evaluation stages. To bridge this gap, this study aimed to monitor & evaluate sustainability performance of the suppliers of a focal manufacturing company in automotive sector with the TBL approach. Toward that end, we questioned and tried to identify first the sustainable supplier selection and monitoring & evaluation differentiating criteria, and then, how we can rank and rate the sustainable suppliers for developmental purposes in the monitoring & evaluation phase. 21 criteria were determined for sustainable supplier performance in monitoring & evaluation by a detailed literature review and taking the opinions of the focal company. Then, decision makers assessed sustainability dimensions and determined criteria related to these dimensions. The weights of dimensions and criteria were calculated by Interval-Valued Intuitionistic Fuzzy AHP method. Then, sustainability performances of selected suppliers from the focal company's portfolio were ranked by using Fuzzy EDAS, Fuzzy CODAS and Fuzzy MOORA methods. The results show that sustainable supplier monitoring & evaluation criteria involve a mix of external criteria (rules and regulations) and internal criteria (suppliers' values). This finding helps us understand how we can have a more relaxed criteria set involving basic external criteria while selecting suppliers to have access to a more innovative and diverse supplier space and then have more challenging internal and external criteria to monitor & evaluate those suppliers toward true sustainability.