ABSTRACT Introduction Quality of life (QoL) captures objective life conditions, subjective wellbeing, and personal aspirations. Interest is growing in ability‐based, patient‐centered instruments, not confounded by health outcomes. The Quality of Life and Function Five Domain Scale (QFS‐5) uses a multi‐dimensional approach to measure QoL emphasizing abilities and life engagement. We describe the development and validation of the QFS‐5 in a large sample of community‐dwelling older adults. Methods The validation sample comprised 1610 participants aged ≥ 50 from the Canadian Platform for Research Online to Investigate Health, Quality of Life, Cognition, Behavior, Function, and Caregiving in Aging (CAN‐PROTECT). Internal consistency was assessed using Cronbach's alpha and item‐total correlations. Confirmatory factor analysis (CFA) evaluated domain structure. Criterion validity was tested through Pearson's correlation with the EuroQol‐5D (EQ‐5D). Convergent and discriminant validity were evaluated from associations with cognitive, mental health, and functional measures. Floor and ceiling effects were investigated. Results The QFS‐5 demonstrated excellent internal consistency ( α = 0.92); CFA supported the proposed domain structure with strong item loadings. Criterion validity was confirmed with correlation of −0.61 against the EQ‐5D; higher symptom burden on related scales were associated with lower QFS‐5 scores. Floor effects were minimal, while modest ceiling effects were observed in some domains. No significant floor or ceiling effects were found in participants with frailty. Conclusion Validity and reliability are established for this ability‐based QoL scale, within a sample of mostly cognitively unimpaired, community‐dwelling older adults. The QFS‐5 aligns with EQ‐5D, demonstrating potential clinical and research utility to measure relevant patient‐reported QoL outcomes.
Ismail et al. (Wed,) studied this question.