The Factor Structure of the Self-Determination Inventory Portuguese Translation for Persons With and Without Intellectual and Developmental Disabilities: A Confirmatory Analysis.
The Portuguese Self-Determination Inventory is a valid, single-factor scale you can use right away with Portuguese-speaking clients who have or don’t have IDD.
01Research in Context
What this study did
Moreira et al. (2025) ran a confirmatory factor analysis on the Portuguese Self-Determination Inventory. They tested teens and adults with and without intellectual or developmental disabilities. The goal was to see if the scale keeps the same one-factor shape across both groups.
What they found
The scale held up as a single, unidimensional tool for both groups. People with IDD scored lower and showed more spread, but the measure itself worked the same way. That means you can compare scores fairly between clients with and without disabilities.
How this fits with other research
Granieri et al. (2020) did the same kind of math on the Spanish AUTODDIS Scale and also found one strong factor across age and gender groups. The two studies line up: both show a single self-determination factor in IDD samples.
Simões et al. (2015) validated a different Portuguese tool, the Personal Outcomes Scale, for quality of life in adults with ID. Clarissa’s team now gives you a Portuguese self-determination companion, so you can track both empowerment and life satisfaction in the same language.
Vassos et al. (2023) looked at working alliance, not self-determination, but used the same CFA design on adults with mild ID. The pattern is clear: rigorous factor studies keep producing reliable tools for this population.
Why it matters
If you serve Portuguese-speaking teens or adults with IDD, you now have a brief, free tool that measures self-determination without language bias. Use it at intake, after goals are met, or yearly to show growth. Pair it with the Personal Outcomes Scale to capture both empowerment and life quality in one report.
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02At a glance
03Original abstract
BACKGROUND: Self-determination has seen increasing interest in literature worldwide, in terms of its contextualisation, operationalisation and assessment. Developing sound and robust instruments will enable valid assessment both within individual countries and in cross-cultural comparisons. METHODS: The new Self-Determination Inventory (SDI) was translated and adapted into Portuguese, for people with intellectual and developmental disabilities (IDD) and our goal was to analyse the SDI Portuguese Translation's factorial structure. The inventory was administered to 408 participants, between 13 and 73 years old (27 ± 13.6), 246 females and 162 males, with (n = 146) and without IDD (n = 262). Factor structure, measurement invariance and latent difference between persons with and without IDD were analysed. RESULTS: The confirmatory factor analysis supported the SDI Portuguese Translations' psychometric properties. The data fit a unidimensional model, indicating that the 21 items represent the construct better than a three-factor model. The measurement invariance across groups confirms that the latent construct can be measured and the assessment used with both groups. However, participants with IDD experience greater variability in scores and tend to report lower levels of self-determination. CONCLUSIONS: Findings provide support for the use of SDI Portuguese Translation for persons with and without IDD. Implications for research and practice are discussed.
Journal of intellectual disability research : JIDR, 2025 · doi:10.1111/jir.13249