Social evaluation of health care versus personal evaluation of health states. Evidence on the validity of four health-state scaling instruments using Norwegian and Australian surveys.

In most of the cost-utility literature, quality-adjusted life-year (QALY) gains are interpreted as a measure of social value. Given this interpretation, the validity of different multi-attribute health-state scaling instruments may be tested by comparing the values they provide on the 0-1 QALY scale with directly elicited preferences for person trade-offs between different treatments (equivalence of numbers of different patients treated). Norwegian and Australian public preferences as measured by the person trade-off suggest that the EuroQol Instrument assigns excessively low values to health states. This seems to be even more true of the McMaster Health Classification System. The Quality of Well-being Scale appears to compress states toward the middle of the 0-1 scale. By contrast, the Rosser/Kind index fits reasonably well with directly measured person trade-off data.