Within the framework established by the Italian Third Sector Code and the recent ministerial directives, evaluation capacity is essential for the innovation and sustainability of Third Sector Entities (ETS): both in terms of external accountability and internal learning, to valorize the quality produced in the communities, and to acquire new professional (and auto-reflexive) competencies. Through a theoretical and methodological analysis, the article explores the evolution of Social Impact Assessment (VIS), its application in Italy, and the proliferation of evaluation models. However, the study highlights how ETS – particularly Volunteer Organizations and Social Promotion Associations – still display methodological gaps and forms of organizational inertia. The Authors propose a flexible, modular and self-reflective approach to VIS, based on mixed methods and integrating quantitative, qualitative, and network dimensions to enhance organizational learning, identity, and community social capital.