Veto Values in Group Decision Making within MAUT - Aggregating Complete Rankings Derived from Dominance Intensity Measures

We consider a group decision-making problem within multi-attribute utility theory, in which the relative im­ portance of decision makers (DMs) is known and their preferences are represented by means of an additive function. We allow DMs to provide veto values for the attribute under consideration and build veto and adjust functions that are incorporated into the additive model. Veto functions check whether alternative performances are within the respective veto intervals, making the overall utility of the alternative equal to 0, whereas adjust functions reduce the utilty of the alternative performance to match the preferences of other DMs. Dominance measuring methods are used to account for imprecise information in the decision-making scenario and to de­ rive a ranking of alternatives for each DM. Specifically, ordinal information about the relative importance of criteria is provided by each DM. Finally, an extension of Kemeny’s method is used to aggregate the alternative rankings from the DMs accounting for their relative importance. price, the location, the size or the age. One of the two might rule out any house smaller than 40m, re­ gardless of house price, location and age, whereas the other might rule out any smaller than 60 m. There­ fore, in this group decision-making scenario, a pos­ sible veto range would be [0,40], ruling out the pur­ chase of any house smaller than 40m, and a possible adjust range would be (40,60], decreasing the utility of the respective house to account for the DM veto values. The veto concept has been variously considered as a real-world approach for representing the lim­ its of DM preferences in the literature.To establish these preferences the veto threshold is represented as a quantifiable measure, which becomes an important tool in multicriteria and group decision-making. In social theory, the concept of veto is justified by the prudence axiom enunciated by Arrow and Raynaud (Arrow and Raynaud, 1986), whose main idea is that it is not prudent to accept highly conflicting al­ ternatives that may result in vulnerable decisions. Re­ garding the previous axiom, Moulin defines the prin­ ciple of proportional veto in a group of DMs (Moulin, 1981), according to which any subset has the right to veto a number of alternatives in proportion to the size of the subgroup. In MCDM problems the concept of veto has been