Design and Validation of the Multidimensional School Social Climate Inventory for Adolescents (MSSCI-A) in Chile.

In Latin America, there is a critical need for validated instruments that capture the multidimensionality of school social climate from an ecological perspective. To fill this gap, this study developed and validated the Multidimensional School Social Climate Inventory for Adolescents (MSSCI-A). Using a non-experimental, cross-sectional design, data were collected from 8949 students across 16 Chilean regions, randomly divided for exploratory and confirmatory analyses. Content validity was ensured through expert judgment with Aiken's V, while item variability was tested in a pilot study. Dimensionality was examined through Exploratory Factor Analysis (EFA) and Exploratory Graph Analysis (EGA), which identified 10 coherent and parsimonious dimensions. These combined expected domains such as Emotional Safety, Collaboration, and Belonging with hybrid factors that reflect how students experience interdependent aspects of school life. The Organizational Structure factor, however, did not meet minimum psychometric standards and was therefore removed. The final model was tested with Confirmatory Factor Analysis (CFA), while internal consistency and convergent validity were supported through Cronbach's alpha, McDonald's omega, and AVE. Findings show that the MSSCI-A demonstrates strong psychometric properties. Overall, it constitutes one of the few validated, multidimensional, and culturally grounded tools in Latin America, with applications in research, educational practice, and policymaking.