A new interval type 2 best worst method and its application to healthcare waste treatment selection problem

The Best Worst Method (BWM) is considered to be a desirable method for multi-criteria decision-making (MCDM) in place of the Analytic Hierarchy Process (AHP) because it reduces the number of pairwise comparisons required and maintains consistency between judgments. However, decision-makers often face uncertainty and must choose between a few similar alternatives, making decision-making more challenging. To address these issues, a new method called interval type 2 Fuzzy Additive BWM (IT2F-ABWM) has been proposed, which uses a fuzzy interval scale to handle uncertain preferences. This method retains the characteristics of the original BWM while simplifying fuzzy calculations by eliminating the fuzzy multiplication operation. Furthermore, a fuzzy consistency index and fuzzy consistency ratio are introduced to check the reliability of the DMs’ preferences. A case study concerning healthcare waste treatment selection is implemented by the proposed IT2F-ABWM to illustrate the practicality of the proposed method. Finally, a comparative analysis is conducted to demonstrate the benefits of the proposed IT2F-ABWM.