Drop Dead: Is Anchoring at 'Dead' a Theoretical Requirement in Health State Valuation?

By convention, values for generic 'preference-based' measures, such as the EQ-5D, are anchored at 1 = full health and 0 = dead. This paper challenges the assumption that anchoring health state values at 'dead = 0' is a necessary condition for values to be used in quality-adjusted life year (QALY) estimation. The authors consider five propositions, using narrative review of the literature and conceptual explication of the problem - - anchoring at 'dead' is not required by theories of scale measurement and utility; - calculating QALY gains does not require a distinction between states better than and worse than dead; - cost-effectiveness analysis does not require that 'dead' has a value relative to health states; - using 'dead' as an anchor causes problems that make studies difficult to conduct and their results difficult to interpret; and - there are alternative states to 'dead' that exhibit favourable properties for anchoring. There is support for each proposition. Anchoring health state values at dead was an arbitrary choice made early in the development of health state valuation methods. The use of dead as an anchor is unnecessary and undesirable because of the methodological and conceptual issues it causes. The authors conclude that, in valuing health states, researchers should 'drop dead'.