Extension of the Regime Method to Group Decision-Making in a q-Rung Orthopair Fuzzy Environment

q-Rung orthopair fuzzy sets (qROFS) constitute a robust extension of Intuitionistic Fuzzy Sets (IFS) and Pythagorean Fuzzy Sets (PyFS).They provide an advanced framework for handling complex information in an uncertain environment.The REGIME method is an MCDM approach used to provide a definitive ranking of alternatives.In the literature, a few extensions have integrated REGIME with IFS and PyFS.However, not only do very few of these extensions address group decision-making problems, but they are also limited when dealing with q-ROFS type data.In this article, we propose an extension of the REGIME method to group decision-making in a qROFS environment.Our methodology proceeds in three phases: aggregation of fuzzy decision matrices, formulation of a non-linear programming model based on qROFS entropy for the objective weighting of criteria, and adaptation of REGIME to evaluate the options.This new methodology extends, for the first time, the REGIME method to a qROFS environment.The proposed method is applied to a numerical example on supplier selection to demonstrate its effectiveness.