A ranking methodology using a new dispersion criterion on a group decision making

This paper discusses a new method using “distance-adjusted covariates” in group decision making. We introduce a distance of opinions between two evaluators in the group, and define it by a distance between two vectors of covariates. When a particular distance between two evaluators is too large compared to others or too small, it tends to cause a bias that disproportionately influences a group plan. The proposed method determines the scale of covariates (grade point) for each evaluator so that the distance of opinions will be adjusted, which makes the influence on the group plan rather equal. Then the method introduces “VDI (Variety Dispersion Index)” that is an index for the equality degree on the influence for the group plan. If a VDI is small, it indicates that the influence on the group plan be equal. The simulation result shows that this method is also useful as a tool to analyze the group behavior by using grade points and VDI. The method can be applicable to AHP when combined with absolute measurement method.