Evaluating Supplier Selection Criteria with Interval Pythagorean Fuzzy AHP

Supplier selection is one of the most critical decisions a business must make today. Especially with the rise of globalization and increasing competition, both the process of selecting suppliers and the criteria considered during selection have gained greater significance. In this context, the purpose of this paper is to determine the importance levels of supplier selection criteria for a furniture manufacturing company. For this purpose, nine criteria—quality, delivery on time, material price, information sharing, after-sales service, lead time, quantity discount, occupational health and safety system, and transportation costs—were evaluated. The Interval-Valued Pythagorean Fuzzy AHP (IVPF-AHP) method was employed to assess the importance levels of these criteria. Based on evaluations from three experts and subsequent calculations, transportation costs emerged as the most critical criterion in supplier selection. This was followed, respectively, by delivery on time, material price, quality, quantity discount, lead time, after-sales service, information sharing, and the occupational health and safety system.