This thesis focuses on decision support in a very complex decision-making context. Typically, to solve such situations, methods of problem structuring are used. However, these methods although applied in the multi-stakeholder framework or group decisions do not always lead to results directly used in a valuation model. Even when this is the case, the data obtained by problem structuring are used as if they came from a single decision maker, thus tending to reduce the effectiveness of the decision and its popular support. In this thesis we attempted to develop a model that incorporates tools that reconcile the appropriate choice of tools for structuring group decision choice and its effective operation in a model of multi-criteria evaluation. In particular, we focused on how processing cognitive maps into value trees. Then we have applied our approach to the practical case of the ‘‘AIDHY” project. Finally, the last part of the thesis is focused on providing a multi-criteria modeling to formally approach the problem of evaluating scenarios, formulated as a multi-criteria sorting problem. Therefore, we constructed a method to observe and configure the behavior of invariants of social acceptability in general, through a sensitivity analysis based on the case of hydrogen energy.
