A concise consensus support model for group decision making with reciprocal preference relations based on deviation measures

Supporting the process of consensus building has become a major research field in group decision making (GDM). The purpose of this paper is to present a consistency consensus based decision support model for GDM based on reciprocal preference relations. Inspired by the concept of a deviation measure between two matrices, an individual consistency index and a group consensus index are presented. In the support model, a consistency control process is designed to make an inconsistent reciprocal preference relation one of acceptable consistency. To achieve a predefined consensus level, an interactive consensus reaching process is provided where the group reciprocal preference relation is seen as a reference when experts change their preferences. Theoretical foundations are then established for the proposed model. The proposed model revises the original information in a simple and straightforward gradual way. In the consensus process, the individual rationality level in terms of consistency is maintained. Two examples are examined to demonstrate the model in practical problems.