A Decision Aid System to Provide Consistent Linguistic Preference Relations

In Group Decision Making, the expression of consistent preferences is often a very difficult task for the experts, specially in decision problems with a high number of alternatives. This difficulty increases when experts are asked to provide their preferences in the form of preference relations because the amount of preference values that are required increases exponentially. This usually leads to situations where an expert may not be able to express all his/her preferences properly and consistently (that is, without contradiction). As a result, eventually the information provided can easily be either incomplete or inconsistent. In this paper we develop a transitivity based support system to aid experts to express their linguistic preference relations in a more consistent way. This interactive system provides the expert with recommendations for the preference values that they have not yet expressed. These recommendations are computed with the aim of maintaining the consistency level of the expert as high as possible.