A theoretical framework for TTO valuations of health.

This paper proposes a theoretical framework, drawing on Hicks utility theory, for the Time Trade-off (TTO) method conventionally used to value health states. We briefly describe that theory and posit four distinctive TTO valuation approaches suggested by it: each of compensating variation and equivalent variation for both gains and losses in health, with valuation of health states in each case derived from trade-offs between health and length of life. Recent developments and research on TTO valuation are placed in the context of this framework. Copyright (c) 2006 John Wiley & Sons, Ltd.