Abstract
A group decision is often believed to be better than individual decision simply because of accumulating all members' knowledge, being able to check errors carefully and so on. The other reason is that the group facilitate creativity and develop new ideas by inspiring each other. For these advantages, the decision makers improve their given information and may revise their opinions referring to the others and the group's as in Delphi Method. While, this paper assumes the synergy effect of decision makers. Someone's consistency may be complemented by the others opinions and/or the integration may create the new value beyond any individual ones. Based on Interval AHP where uncertainty among comparisons are reflected into interval weights, the individual evaluations, their sum, and the group evaluations are examined.
