A formal approach to handling conflicts in multiattribute group decision making

The Hypothetical Equivalents and Inequivalents Method (HEIM) has been developed to support decision making in multiattribute problems where one decision maker is making the decision. In this paper HEIM is modified to support group decision making in multiattribute problems, resulting in the Group Hypothetical Equivalents and Inequivalents Method (G-HEIM). Instead of aggregating attribute weights or overall alternative values from each individual as is common in other group decision methods, G-HEIM operates by aggregating individual preferences. It is recognized that in group decision making, common preferences among group members can rarely be guaranteed, unless individual freedom is greatly limited. G-HEIM instead allows individuals to freely express preferences over a number of hypothetical alternatives and then explores the level of conflict or differences from the aggregated group preferences. The relationship between the level of conflicting preferences and the usability of the resulting decision is also directly studied using the G-HEIM. An automotive selection example is used to illustrate the approach.