Ranking multi-attribute alternatives on the basis of linguistic labels in group decisions

This paper presents a new approach based upon qualitative reasoning techniques for representing and synthesising the information given by a group of evaluators. A mathematical formulation is developed that contributes to decision-making analysis in the context of multi-attribute and group decision-making. This method, is applied in choice and ranking problems and can work at different precision levels. To represent non-trivial domain knowledge, the patterns or alternatives to be ranked are characterised by a set of features, which are evaluated by each member of the group through linguistic labels corresponding to ordinal values. Different levels of precision are considered to draw the distinctions required by evaluators' reasoning processes. The method used for ranking alternatives is based on comparing distances against an optimal reference point. A theorem on the consistency of the proposed method is presented and proved. Three real-life applications are presented to outline areas of management where the proposed method has been implemented and achieved interesting results.