A Literature Review on Supplier Selection Problem and Fuzzy Logic

Given the recent increasing competition in global market, supplier selection and evaluation has attracted a great deal of attention especially at academic levels. Supplier selection problem is a complex problem since there exist a great number of unpredictable and uncontrollable factors which have a huge impact on decision-making process. Due to this complexity, there are several criteria that must be taken into consideration such as cost, quality, on-time delivery, proximity of suppliers, long-term relationship etc. Although some of these criteria (quantitative) can be expressed using pure numeric scales, some (qualitative) are linguistic due to the human assessments which contain some degree of subjectivity. Since involvement of human assessment causes vagueness for deterministic models, the authors apply fuzzy logic which enables the decision makers to be able to convert their linguistic expressions into fuzzy numbers with the help of fuzzy membership functions. Considering that fuzzy logic plays a vital role in solving multi-criteria supplier selection problem, this paper aims to present a review of supplier selection problem and its relation with fuzzy logic. In this paper, several studies that highlight supplier selection problem and the importance of fuzzy logic involvement in the problem have been reviewed. An analysis of multi-criteria decision-making methods for supplier selection problem is conducted.