Ben Amor, S.Martel, M.-A.2011-11-252011-11-2520112011-11-25WP.2011.08http://hdl.handle.net/10393/20445http://dx.doi.org/10.20381/ruor-909In this paper we propose a new distance measure between two preorders where the indifference, strict preference, weak preference and incomparability relations are considered. This distance measure is then used in the aggregation stage of a multiple criteria aggregation procedure for mixed evaluations designed to deal with different kinds of information imperfections. Introducing the weak preference relation allows for more nuance and flexibility to the decision- maker in this context.