Abstract The method presented in this paper is an extension of the promethee, one of the most known multicriteria outranking methods. This extension consists in a more detailed investigation of the differences existing among the performances of the actions examined, achieved through the notion of ideal and anti-ideal alternative. Hence, the state of strict preference relating various pairs of actions can be differentiated with reference to the extreme performances attained by the alternatives under consideration. The more accurate description of the reality leads to a relatively more reliable ranking of the available solutions and allows the exploitation of the results for the construction of a cardinal scale, assigning to each action a numerical value between 0 and 1. The quantitative differentiation of the alternatives, thus achieved, gives another dimension of information, which is extremely useful for the decision making process. A comparative study of the two methods shows the greater sensitivity of exprom and its ability to reflect in the quantitative results any probable deviation in the initial data of a problem. This sensitivity is accompanied with a greater stability, due to the smoothing of the discontinuities characterizing most preference functions in promethee.