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

Supported decision-making is central to rights-based practice, but psychometric evidence in Catalan and Spanish is limited.

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.

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.

Findings support interpreting Catalan and Spanish SDMI scores at domain and subscale levels to assess supported decision-making and inform support planning.