An Extended Dominance-Based Rough Set Approach to Group Sorting Decision Making

The main difficulty with application of many existing multiple criteria group sorting decision aiding methods lies in acquisition of the decision maker´s preferential information. Very often, this information has to be given in term of preference model parameters, like importance weights, substitution rates and various thresholds. It is acknowledged, however, that decision makers may prefer to make exemplary decisions than to explain them in terms of special functional model parameters. For this reason, we present a rough set approach to group sorting decisions making in this paper. To deal with decision of multiple decision makers we extend Dominance-based Rough set by introducing specific concepts related to dominance with respect to minimal profiles of evaluations given by multiple decision makers. Our approach differs from existing group decision approaches for we characterize conditions for a consensus attainable by multiple decision makers considered as a whole. Such a perspective permits to handle interactions between decision makers. The usefulness of this approach is illustrated by an example.