A method for large group decision-making based on evaluation information provided by participators from multiple groups

• A new kind of large group decision-making (LGDM) problem is formulated.
• A framework for solving the LGDM problem is presented.
• A technology for determining the decision weights of different subgroups is proposed.
• An approach to ranking alternatives in LGDM analysis is presented.
• A case study is used to illustrate the use of the proposed method.

Large group decision-making (LGDM) is a special group decision-making (GDM) problem, in which a large number of persons take part in decision process, while research concerning this issue is still relatively scarce. The objective of this paper is to develop a method to solve the LGDM problem, in which a large number of persons from multiple groups take part in the decision process and express their personal evaluations on the alternatives according to the pre-established identifier set. In the method, the percentage distribution on evaluations of each group concerning each alternative is determined. The decision weight of each group concerning each alternative is obtained by aggregating the subjective weight, which is provided by the organizer, and the objective weight, determined according to the level of consensus among participators' evaluations. According to the percentage distributions and decision weights, the dominance degrees on pairwise comparisons of alternatives are calculated, and a ranking of alternatives can be determined using the PROMETHEE II method. Finally, an example is given to illustrate the use of the proposed method.