Currently, health state values are usually obtained from members of the general public trying to imagine what the state would be like rather than by patients who are actually in the various states of health. Valuations of a health state by patients tend to vary from those of the general population, and this seems to be due to a range of factors including errors in the descriptive system, adaptation to the state and changes in internal standards. The question of whose values are used in cost-effectiveness analysis is ultimately a normative one, but the decision should be informed by evidence on the reasons for the differences. There is a case for obtaining better informed general population preferences by providing more information on what it is like for patients (including the process of adaptation).