What if 0 is not equal to 0? Inter-personal health utilities anchoring using the largest health gains

Prioritizing health technologies requires comparisons of improvements in longevity or quality of life (QoL), or both. For this purpose, value sets are constructed that contain weights assigned to health states based on societal preferences. I show that how this is typically done may distort the results by giving unjustifiably larger impact to individuals who prioritize improvements in QoL over longevity. The problem results from equating the utility differences between being dead and full health across people, ignoring the fact that interpersonal utility comparisons are forbidden (or at least problematic) in economics. I propose another approach: the numerical value of maximal health gain (either in longevity or QoL) is assumed to be equal across individuals, to remove the impact of the range of utilities differing between people. I test this approach using EQ-5D-5L and EQ-5D-3L utilities elicited in Poland for two modeling techniques: a simple econometric model and a Bayesian one that accounts for censoring. The proposed approach increases the utilities of the worst health state: from [Formula: see text] to [Formula: see text] in EQ-5D-5L and from about [Formula: see text] to [Formula: see text] in EQ-5D-3L. In the Bayesian approach, the impact is greater: from [Formula: see text] to [Formula: see text] for EQ-5D-5L and from [Formula: see text] to [Formula: see text] for EQ-5D-3L. I discuss some normative arguments why the proposed approach may be more justifiable for aggregating individual preferences for health outcomes.