Incorporating negative values into the Analytic Hierarchy Process

This paper describes why and how ratio scaled multiple criteria analysis techniques, such as the Analytic Hierarchy Process (AHP), should allow for a subtraction mechanism whereby negative preference (aversion) is combined with positive preference. The main contribution of the paper is a demonstration of how the current imposition of a strictly positive additive value structure can lead to incorrect preference ratios and even incorrect ranking of alternatives. The proposed preference elicitation and computation method solves these problems in a simple and intuitive manner.