Abstract

ELECTRE TRI, a family of multi-criteria methods used to sort alternatives into preference-ordered categories, defines an outranking function to measure the membership degree of an alternative to a category, whenever imprecise evaluations are available. Recent extensions use Hesitant Fuzzy Sets (HFS) to consider uncertain evaluations. However, deterministic parameters are considered, which avoids the application to cases in which non-fuzzy scores and unstable parameters are available. In this study, an approach is proposed for: 1) modeling hesitant outranking functions originated from unstable parameters provided by several DMs; 2) using the HFS to calculate the ELECTRE TRI-C indices; 3) reducing the DMs cognitive effort when they are asked to provide information. An application to supplier development is presented by using ELECTRE TRI-C. Results are compared by using different HFS aggregation operators and sensitivity analysis shows that a robust conclusion can be obtained. Future lines of research are also suggested.