1 Consensus Based Onfuzzy Coincidence

The problem of consensus reaching in the group decision making situations is considered. Assuming a heterogeneous and linguistic group decision making context various linguistic consensus measures are presented to guide the consensus process. Considering linguistic preference relations to provide experts' opinions, they are deened in three levels of action: level of the pairs alternatives, level of the alternatives, and level of the relation, and therefore there are three measures: pair linguistic consensus measure, alternative linguistic consensus measure and relation linguistic consensus measure. They are based on a exible idea of the concept of coincidence, which is de-ned as a fuzzy set in each level from the closeness observed among experts' opinions. This allows us to know with more precision the consensus state at all times and to guide the consensus reaching process more adequately. In order to easily understand the meaning of these measures, they are assessed on a label set diierent to that used to express the experts' opinions. All the measures are obtained using linguistic quan-tiiers, to express the concept of majority of experts and alternatives, and the LOWA operator to aggregate linguistic information.