The Social Growth Index: measuring socioeconomic resilience at the municipal level in Italy

The Social Growth Index (SGI) provides a multidimensional measure of socioeconomic resilience and a ranking of Italian municipalities. The index integrates spatially disaggregated estimates of Gross Domestic Product (GDP), obtained through Fixed Rank Kriging (FRK), with demographic information to evaluate local resilience across the period 2010–2022. Three standardized and spatially harmonized variables are considered: economic density (GDP per km2), GDP per capita, and population density. These dimensions jointly describe the capacity of each municipality to sustain economic activity, individual well-being, and demographic vitality. Resilience is assessed through the Copeland method, which aggregates the relative performance of municipalities across the three criteria into a single ordinal score. The resulting SGI highlights a clear North–South divide in Italy, with higher resilience in Northern and Central regions—particularly Lombardy, Emilia-Romagna, and Tuscany—and lower resilience in Southern regions and insular territories. Temporal comparisons show structural persistence in the most resilient urban areas and gradual improvements in medium-sized cities. Finally, the SGI is compared with the Municipal Fragility Index (IFC) developed by ISTAT, revealing a strong inverse relationship between resilience and fragility. The SGI thus offers a coherent and spatially consistent framework for monitoring territorial resilience and supporting evidence-based regional policy design.