Strategies to Manage Ignorance Situations in Multiperson Decision Making Problems

Multiperson decision making problems involve using the preferences of some experts about a set of alternatives in order to find the best of those alternatives. However, sometimes experts cannot give all the information that they are required. Particularly, when dealing with fuzzy preference relations they can avoid giving some of the preference values of the relation. In the literature these incomplete information situations have been faced giving procedures which are able to compute missing information from the preference relations. However, these approaches usually need at least a piece of information about every alternative in the problem. In this paper, several strategies to manage total ignorance situations, that is, situations where an expert does not provide any information on at least one alternative are presented, and their advantages and disadvantages analised.