RESUMO
OBJECTIVE: To describe the validation of an instrument to assess the mental capacity of an individual to sign an enduring power of attorney. METHODS: An instrument named Capacity Assessment to Sign an Enduring Power of Attorney (CASEPA) was developed following a literature review, focus group discussions, expert reviews, and pilot testing. Chinese persons aged ≥ 60 years who had a range of cognitive abilities were recruited from elderly care centres in Hong Kong to explore its psychometric properties. RESULTS: A total of 85 participants were included. For inter-rater reliability, the intraclass correlation coefficient was 0.93 for understanding, 0.87 for appreciation, and 0.84 for reasoning. For internal consistency, the Cronbach's alpha was 0.75 for understanding, 0.74 for appreciation, and 0.86 for reasoning. The content validity was examined by an international expert in mental capacity and psychiatry and by 5 local experts in the fields of mental health, law, psychiatry, psychology, and geriatrics. The clinician ratings correlated with the ability score for understanding (r = 0.74, p < 0.001), appreciation (r = 0.73, p < 0.001) and reasoning (r = 0.73, p < 0.001). CONCLUSION: The CASEPA is a potentially useful tool to assess the mental capacity of an individual to sign an enduring power of attorney.