Managing multi-granularity linguistic information in qualitative group decision making: an overview

Linguistic term sets are usually preferred to represent evaluations and preferences in qualitative group decision making (QGDM). Due to the different backgrounds and levels of knowledge of experts, linguistic term sets with different cardinality and/or semantics are used. Hence, it is vital to manage these linguistic terms from distinct information sources in QGDM. In this paper, we present a comprehensive review on relative developments of multi-granularity linguistic term sets by several perspectives, such as the transformation techniques, the aggregation functions, decision making processes and the applications. Finally, some possible directions for future research are pointed out as well.