Approximate Reasoning in the Modeling of Consensus in Group Decision

In this paper we propose an approach to consensus reaching based on linguistically expressed individual opinions and on so-called opinion changing aversion. We operate within this basic context: there is a group of experts which must choose a preferred alternative from a finite set of admissible ones according to several criteria. Each expert is called upon evaluate linguistically the alternatives in terms of their performance with respect to each criterion. The task of the experts is to reach some agreement during a consensus reaching process directed by a third person called the moderator. The experts are expected subsequently to change their testimonies until sufficient agreement (consensus) has been reached. The measure of consensus depends on a function estimated for each expert according to his/her aversion to opinion change.