## 5 Conclusions
From the tendential coincidence between the primary goals of the public and private operators, a positive perspective can be derived on the potential collaboration for the development of the water sector, especially in the most disadvantaged areas. In terms of future perspectives, it could be interesting to apply the multicriteria model proposed in other Italian regions or other countries to evaluate its effectiveness in different contexts and compare the results obtained. Secondly, it could be useful to test the model concerning other relevant criticalities that characterize the water resources management process. Thirdly, it could be useful to evaluate the impact of the investment strategy suggested by the model on the sustainable management of water resources and the rights of the populations concerned through the analysis of field data and the study of the outcomes of the implemented policies. Furthermore, the model could be used for improving investment planning in other sectors, such as energy and sustainable construction, using specific criteria defined based on recurring criticalities and integrating sector regulations. Conceptualization, M.M., L.D. and G.D.M. ; methodology, M.M., L.D. and G.D.M. ; software, M.M., L.D. and G.D.M. ; validation, M.M., L.D. and G.D.M. ; formal analysis, M.M., L.D. and G.D.M. ; investigation, M.M., L.D. and G.D.M. ; data curation, M.M., L.D. and G.D.M. ; writing--original draft preparation, M.M., L.D. and G.D.M. ; writing--review and editing, M.M., L.D. and G.D.M. ; supervision, M.M., L.D. and G.D.M. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The data presented in this study are available upon reasonable request from the corresponding author. The authors declare no conflict of interest. The analytic hierarchy process (AHP) is a decision-support technique developed by [PERSON] in the 1970s [44]. It is a multicriteria analysis method, which makes it possible to evaluate and compare different alternatives based on a set of hierarchical criteria. The analytic hierarchy process (AHP) technique owes its name to its analytical and hierarchical methodology for evaluating criteria and alternatives. The analytic approach of the AHP is based on the idea that complex decisions can be broken down into simpler and more manageable components. Furthermore, the AHP hierarchical approach requires that objectives, criteria and alternatives are organized in a hierarchical structure, in which each level represents a decreasing degree of importance. The use of a hierarchical structure is a distinctive element of the AHP, as it allows the complexity of decisions to be represented more clearly and intuitively. Furthermore, the hierarchy helps us to focus on the most important elements of the decision and to reduce the complexity of the problem [45; 46; 47]. In the analytic hierarchy process (AHP), the hierarchical structure of a decision problem is divided into the following levels:  
* Goals: the general objectives that you want to achieve. They are the highest level of the hierarchy and can be defined generically or specifically. In the simplest cases, the goal is unique;
* Criteria: the aspects that must be considered for the evaluation of the objectives. They are the second level of the hierarchy and are categorized according to their degree of importance to the overall objective. Sometimes a further intermediate hierarchical level can be introduced between the criteria and the alternatives by defining a series of sub-criteria. These represent the specific aspects that must be considered for the evaluation of the criteria;
* Alternatives: the specific options that must be evaluated for the final choice. They are the last level of the hierarchy and are evaluated according to the criteria and sub-criteria defined in the higher levels. Within the AHP, the factors (criteria, sub-criteria or alternatives) within the same level are to some extent related to each other.