New and Robust Tests of QALYs when Health Varies over Time

This paper performs new and more robust tests of the QALY model when health varies over time. Our tests do not involve confounding assumptions and are robust to violations of expected utility. Our results support the use of QALYs at the aggregate level, i.e. in economic evaluations of health care. At the individual level, there is less support for QALYs. The individual data are, however, largely consistent with a more general QALYtype model that remains tractable for applications.