Group decision directly from group members' judgments

The group decision making is discussed from the view of Analytic Hierarchy Process (AHP), by which the priority weights of alternatives are induced from the pairwise comparison matrix given by a decision maker. This paper uses Interval AHP which induces interval priority weights to reflect uncertainty of the given information. In the problem setting of the group decision making, all group members individually give matrices. Two different ways to aggregate individual opinions have been proposed. One is to aggregate the given information about the comparisons and the other is to aggregate the induced priority weights. This paper proposes straightforward approaches without aggregation steps. The priority weights of alternative as overall evaluations of the group are obtained directly from all the given matrices. They are obtained based on strict or rough inclusion relation between the given comparisons and their approximations consisting of the collective interval priority weights.