Encouragement of Group Decisions Beyond the Sum of the Individuals based on Possible Estimations

The decision problem in this paper is to induce the preference range of a group, for which Interval AHP is suitable because of an interval weight. Three crucial factors, namely, constructive conflict, consideration, and closure, are considered in decision making with respect to Interval AHP. Constructive conflict is encouraged by giving and modifying judgments independently. For fair consideration, the group decision is specified from the possible aggregation of all of the judgments, which could go beyond any of them individually. To support an appropriate closure, the judgment is scrutinized from several viewpoints in reconsideration and it avoids from inconsistent and opportunistic modification.