Axiomatic properties of inconsistency indices for pairwise comparisons

Abstract

Pairwise comparisons are a well-known method for the representation of the subjective preferences of a decision maker. Evaluating their inconsistency has been a widely studied and discussed topic and several indices have been proposed in the literature to perform this task. As an acceptable level of consistency is closely related to the reliability of preferences, a suitable choice of an inconsistency index is a crucial phase in decision-making processes. The use of different methods for measuring consistency must be carefully evaluated, as it can affect the decision outcome in practical applications. In this paper, we present five axioms aimed at characterizing inconsistency indices. In addition, we prove that some of the indices proposed in the literature satisfy these axioms, whereas others do not, and therefore, in our view, they may fail to correctly evaluate inconsistency.

Keywords:

• pairwise comparisons
• inconsistency indices
• axiomatic properties
• analytic hierarchy process

Acknowledgements

We would like to thank professors Benedetto Matarazzo and Salvatore Greco for their encouragement on pursuing this research topic. We are also grateful to the referees and we acknowledge the participants in the scientific publishing seminars organized by the Systems Analysis Laboratory, Aalto University, for their valuable comments.