Self vs. other, child vs. adult. An experimental comparison of valuation perspectives for valuation of EQ-5D-Y-3L health states

Objectives EQ-5D-Y-3L health states are valued by adults taking the perspective of a 10-year-old child. Compared to valuation of adult EQ-5D instruments, this entails two changes to the perspective: (i) child health states are valued instead of adult health states and: (ii) health states are valued for someone else instead of for oneself. Although earlier work has shown that these combined changes yield different values for child and adult health states that are otherwise equal, it currently remains unclear why. Hence, we aimed to disentangle the effects of both changes. Methods A sample of 205 students (mean age: 19.48) was surveyed. Each respondent completed visual analogue scale (VAS) and time trade-off (TTO) tasks for five EQ-5D-Y-3L states, using four randomly ordered perspectives: (i) self-adult (themselves), (ii) other-adult (someone their age), (iii) self-child (themselves as a 10-year-old), (iv) other-child (a child of 10 years old). We compared how each perspective impacted outcomes, precision and quality of EQ-5D-Y-3L valuation. Results Overall, differences between perspectives were consistent, with their direction being dependent on the health states and respondents. For VAS, the effect on outcomes of valuation depended on severity, but variance was higher in valuation with child perspectives. For TTO, we observed that EQ-5D-Y-3L states valued on behalf of others (i.e., children or adults) received higher valuations, but lower variances. Conclusion The use of a different perspective appears to yield systematic differences in EQ-5D-Y-3L valuation, with considerable heterogeneity between health states and respondents. This may explain mixed findings in earlier work.