An Empirical Comparison of the Disability Wellbeing Index (DWI) and ASCOT-SCT4 in Disability

Purpose The Disability Wellbeing Index (DWI) is a new preference-based outcome measure developed to reflect what matters most to people with disabilities. We examined the psychometric properties of the DWI in its Standard and Easy English versions and compared them with the Adult Social Care Outcomes Toolkit (ASCOT) instruments (ASCOT-SCT4 and ASCOT-SCT4-ER, the Easy Read version). Methods We conducted an online survey of National Disability Insurance Scheme (NDIS) participants aged ≥ 15 years (n = 1,871) in 2024. DWI scores were derived using an Australian preference-based algorithm, and ASCOT scores using UK preference weights. Convergent validity was assessed using Spearman’s correlations across total utility scores and domain items, separately by survey version and age group. We examined underlying constructs with exploratory factor analysis (EFA), and known-groups validity using regression analyses based on self-rated health, self-advocacy, meaningful leisure activities, and decision-making autonomy. Results Thirty-nine per cent completed the Easy English/Read version, and 30% were aged 15–24 years. Correlations between DWI and ASCOT were moderate for young people (ρ = 0.61 Easy Read/English; ρ = 0.66 Standard) and strong for adults (ρ = 0.74 Easy Read/English; 0.75). Convergence was strongest for safety items, whereas weaker for dignity items. EFA indicated partial overlap in underlying constructs. Known-groups validity was supported for both measures. Conclusions The findings support the construct validity of DWI. Although DWI and ASCOT are related measures, they focus on different but overlapping aspects. The DWI places a stronger emphasis on general wellbeing, while the ASCOT focuses on social care experiences.