MENTOR: A graphical monitoring tool of preferences evolution in large-scale group decision making

Group decision making problems aim to manage situations in which two or more experts need to achieve a common solution to a decision problem. Different rules and processes can be applied to solve such problems (e.g. majority rule, consensus reaching, and so on), and several models have been proposed to deal with them. Some difficulties may arise in group decisions, being most of them caused by the presence of disagreement positions amongst experts. Given that group decision making problems have classically focused on a few number of experts, such difficulties have been relatively manageable by means of supporting tools based on textual or numerical information. However, such tools are not adequate when a large number of experts take part in the problem, therefore an alternate tool that provides decision makers with more easily interpretable information about the status of the problem becomes necessary. This paper proposes a graphical monitoring tool based on Self-Organizing Maps so-called MENTOR, that provides a 2-D graphical interface whose information is related to experts' preferences and their evolution during group decision making problems, and facilitates the analysis of information about large-scale problems.