Supported Decision-Making Inventory: Psychometric Validation of the Catalan and Spanish Versions.

BACKGROUND: Supported decision-making is central to rights-based practice, but psychometric evidence in Catalan and Spanish is limited. METHODS: The Supported Decision Making Inventory (SDMI) was translated and adapted for use in Catalan and Spanish. Content validity, internal structure, reliability, measurement invariance and construct-related evidence were examined in 510 adults with intellectual and developmental disabilities receiving services from providers in Catalonia. RESULTS: Expert ratings provided content validity evidence. Confirmatory factor analysis supported the six-factor model (CFI = 0.925, TLI = 0.916, RMSEA = 0.055 and SRMR = 0.055) and scalar invariance across interview language. Reliability evidence varied across domains and subscales, with stronger estimates for environmental demands and decision-making supports than for personal factors. Construct-related evidence was stronger for environmental demands and decision-making supports than for personal factors. CONCLUSIONS: Findings support interpreting Catalan and Spanish SDMI scores at domain and subscale levels to assess supported decision-making and inform support planning.