Aggregation of group members´ opinions based on two principles

In this paper, group decision making is discussed from the view of aggregating the members´ opinions. At first, the individual preferences are obtained by Interval Analytic Hierarchy Process (Interval AHP), which can handle subjective judgments and reflect uncertainty of information. The interval priority weights of alternatives are induced from the pairwise comparison matrix given by a decision maker easily. They help decision makers to reveal the differences and similarities between their own opinions and others concretely, and encourage them to reduce their communication barriers. Then, the individually obtained preferences are aggregated so as to reach the final group decision. The aggregation models from two viewpoints, such as decision makers and alternatives, are proposed. The former model emphasizes the members´ consensus by reducing their dissatisfaction for the aggregation. The latter model emphasizes estimating the plausible values of alternatives by taking the essential part of many decision makers´ opinions on each alternative.