Exploring differences – some thoughts for discussion on a mathematical representation of differences among a decision group

This paper presents a mathematical representation of a decision group process, emphasizing the differences among the preferences of all group members. An underlying assumption is that group members can be concerned with different sets of criteria and preference parameters. Moreover, if some group members consider the same criterion, it is possible to have different evaluations of the alternatives according to that criterion. Even the information processing method to achieve the results can differ among the elements of the group. The mathematical representation allows to explicitly reflect the differences among the elements of the groups through differences on the preference parameters, considering another criterion, differences on the evaluation of the alternatives or through differences on the results of the information processing methods. We build a matrix with the differences stemming from the pair wise comparisons of each member's individual decision making process and then we point out some techniques to explore this matrix. In this setting it is not proposed to create a single group result; rather it is intended to provide tools in order that each decision maker can explore the differences between her/his opinions and the group.