Test-Retest Reliability of EQ-5D-Y-3L Best-Worst Scaling Choices of Adolescents and Adults

There is an increasing interest to obtain adolescents' own health state valuation preferences and to understand how these differ from adult preferences for the same health state. An important question in health state valuation is whether adolescents can report preferences reliably, yet research remains limited.This study aims to investigate the test-retest reliability of best-worst scaling (BWS) to elicit adolescent preferences compared with adults.Identical BWS tasks designed to value 3-level version of EQ-5D-Y health states were administered online in samples of 1000 adolescents (aged 11-17 years) and 1006 adults in Spain. The valuation survey was repeated approximately 3 days later. We calculated (1) simple percentage agreement and (2) kappa statistic as measures of test-retest reliability. We also compared BWS marginal frequencies and relative attribute importance between baseline and follow-up to explore similarities in the obtained preferences.We found that both adolescents and adults were able to report their preferences with moderate reliability (kappa: 0.46 for adolescents, 0.46 for adults) for best choices and fair to moderate reliability (kappa: 0.39 for adolescents, 0.41 for adults) for worst choices. No notable difference was observed across years of child age. Higher consistency was observed for best choices than worst in some dimensions for both populations. No significant differences were found in the relative attribute importance between baseline and follow-up in both populations.Our results suggest that BWS is a reliable elicitation technique to value 3-level version of EQ-5D-Y health states in both adolescents and adults.