The article presents the results of an ex-post evaluation of the local development program promoted by Fondazione con il Sud in the territory of Castelbuono. The aim of the work is to analyse the extent to which the intervention contributed to strengthening local social infrastructure, understood as the consolidation and reorganization of collaborative relationships among territorial actors. The evaluation design integrates Social Network Analysis and Nominal Group Technique within a mixed methods perspective, combining structural network analysis and a participatory device for constructing evaluative judgment. The hybridization of quantitative and qualitative tools enables the articulation of objectification of relational configurations with dialogical interpretation of observed changes, in accordance with the participatory evaluation approach. The article proposes a methodological reflection on the integrated use of SNA in evaluation contexts, highlighting its potential in producing shared knowledge about local development processes.