Browsing by Author "Vetschera, Rudolf"
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- Approaches to suggest potential agreements: Perspectives of mediation with incomplete informationPublication . Sarabando, Paula; Dias, Luís; Vetschera, RudolfIn bilateral Negotiation Analysis, the literature often co nsiders the case of complete information. In this context, since the negotiators know the value functions of both parties, it is not difficult to calculate the Pareto frontier and the Pareto efficient soluti ons for the negotiation. Thus rational negotiators can reach agreement on this frontier. However, these approaches are not applied in practice when the parties do not have complete information. The research question of our work is “It is possible to help negotiators achieving an efficient soluti on if they do not have complete information regarding the different parameters of the model?”. We propos e to obtain information regarding the preferences of negotiators during the negotiation process , in order to be able to propose alternatives close to the Pareto frontier. During this work we will presen t three approaches to help a mediator proposing a better solution than the compromise the negotia tors have reached or are close to reach.
- Information levels in additive group decision models under incomplete information: Bridging the cardinal ordinal gapPublication . Vetschera, Rudolf; Dias, Luís; Sarabando, PaulaIn the literature, several models for group decision making based on the additive aggregation of group members’ utility or value functions have been proposed (Keeney and Kirkwood 1975; Dyer and Sarin 1979; Keeney and Nau 2011). These group aggregation rules usually are based on systems of axioms very similar to those formulated by Arrow (1963) for the case of aggregating ordinal preferences. In contrast to aggregation of ordinal preferences, aggregation of cardinal alues is thus possible in groups. However, it requires group members to specify their preferences in cardinal form, by assigning utility scores to alternatives. This could be difficult for group members, in particular if this information should be provided exactly.
- Levels of incomplete informationin group decision models – A comprehensive simulation studyPublication . Vetschera, Rudolf; Sarabando, Paula; Dias, LuisWe present a comprehensive computational study on the effects of providing different forms of incomplete preference information in additive group decision models. We consider different types of information on individual preferences, and on weights of the group members, and study their effects on conclusiveness, ef fi ciency and fairness of outcomes at the group level. Furthermore, we analyze possible violations of the axiom of independence of irrelevant alternatives (IIA) as well as the impact of problem characteristics, in particular initial agreement between group members. Our results indicate that providing information in the form of a ranking of differences between consecutive alternatives comes close to providing exact cardinal preference information in several outcome dimensions. However, group decision procedures based on incomplete preference information also show a significant amount of violations of the IIA axiom.
- Mediation with Incomplete Information: Approaches to Suggest Potential AgreementsPublication . Sarabando, Paula; Dias, Luís; Vetschera, RudolfIn bilateral Negotiation Analysis, the literature often considers the case of complete information. In this context, since the negotiators know the value functions of both parties, it is not difficult to calculate the Pareto efficient solutions for the negotiation. Thus rational negotiators can reach agreement on this frontier. However, these approaches are not applied in practicewhen complete information is not available. The research question of ourwork is “It is possible to help negotiators achieving an efficient solution in the absence of complete information regarding the different parameters of the model?”. We propose to derive incomplete information about the preferences of negotiators from the statements they make and the offers they exchange during the negotiation process. We present and discuss three approaches that use this information in order to help a mediator proposing a better solution than the compromise the negotiators have reached or are close to reach.