Measuring preference-based quality of life in children aged 6-7 years: a comparison of the performance of the CHU-9D and EQ-5D-Y-the WAVES Pilot Study.

PURPOSE: To examine the performance of the child health utility 9D (CHU-9D) and EuroQol 5D-youth (EQ-5D-Y) in children aged 6-7 years. METHOD: The CHU-9D and EQ-5D-Y were interviewer-administered to 160 children aged 6-7 years at six schools across the West Midlands. Missing values, time taken to complete instruments and interviewer ratings were recorded to assess feasibility/acceptability. Construct validity was assessed by testing convergent validity hypotheses. Reliability was examined via a test-retest of a sub-sample. Psychometric properties were further examined by exploring distributions of utility scores, qualitative notes and design of the questionnaires. RESULTS: No missing responses were recorded with over 80% of children's understanding being rated as good/excellent for both questionnaires. The average completion time for both instruments was less than 3 minutes, demonstrating excellent feasibility/acceptability. Evidence of construct validity was recorded with 12 of the 13 convergent hypotheses being supported. Test-retest reliability was relatively poor for both instruments with weighted kappa coefficients ranging from fair to moderate. CONCLUSION: Children aged 6-7 years can feasibly complete utility instruments when interviewer-administered. The reliability of the instruments is of concern and requires further study. With respect to content validity and other psychometric properties, the CHU-9D is favoured to the EQ-5D-Y. Until the EuroQol group produces tariff values for the EQ-5D-Y, we recommend that the EQ-5D-Y is not used for utility elicitation in this age group.