Robust and neutral methods for aggregating preferences into an outranking relation

Definitions are proposed for the concepts of robustness and neutrality of a decision-aid method. They are illustrated on the problem of aggregating preferences into an outranking relation in the presence of an importance relation on the criteria. We show that the concepts allow the analyst to better understand how the methods are grounded and provide him with arguments to justify the choice of one method instead of another. (C) 1999 Published by Elsevier Science B.V. All rights reserved.