A multicriteria decision aid perspective that guides an incremental development of knowledge and fosters relationships and decisions

“Ivrea, industrial city of the 20th century”, is the 54th UNESCO site in Italy, and it has been in the World Heritage List since July 2018. Its inclusion was the result of a complex decision process, which needs to be reactivated to enhance this large, unitary urban system of great historical, architectural and environmental value. The huge dimensions and extreme heterogeneity of the built heritage, the weakness of the socio-economic context, and the dynamics of the public and private organisations have generated a complex situation, which hinders the enhancement of the whole UNESCO site. A methodology that integrates two decision aid approaches can deal with and reduce these complexity factors, to guide the incremental development of knowledge and to foster relationships that facilitate the process reactivation. A Problem Structuring method was used to structure the decision problems and logically synthesise fragmented knowledge. Multicriteria models and methods were used to analytically describe the space of action and propose examples of how alternative policies, enhancement activities or projects can be analysed and evaluated, to be ranked or selected. The paper describes the problem situation and how these methods were integrated and used. The study aims to underline the complementarity of the different decision aid approaches and to show how logical and analytical models, applications of tools and results can be proposed to create an effective communication process, both at technical level and with stakeholders who are willing to participate in preparatory workshops.