How to support decisions and guarantee robustness in Multi Criteria Decision Aid when the preference system is not “accessible”

Several studies that present Multi Criteria (MC) models and the use of MC methods to support decisions have been developed without the active presence of a decision maker. The natural question that arises from this observation is “can a decision aiding intervention that guarantees robust conclusions be developed in these contexts? A positive answer has been obtained from a recent intervention in a public administration, with a team that had to construct a procedure and a system to monitor projects which a Piedmont Region law had financed. In this context, an MC method, ELECTRE TRI, has been applied to the problem, first to explain a possible way of using the acquired information and then to support decisions on any modifications and/or integrations of the activities for future law applications. Interaction with the decision maker’s preference system was not possible in the first phase of the work and was very limited in the last phase. Several devices that had to be adopted to guarantee robustness of the intervention and of its conclusions are described in the chapter.