Respondents are asked how many outcomes of type x would be considered as valuable as saving the life of one young person. This direct elicitation allows all aspects of the given health outcome to be taken into account, including the initial health states as well as the extent of potential gains in health and the characteristics of the persons who would benefit. Nord proposes this unit of measure as a common denominator for all societal investments in health and longevity improvements.
The SAVE measure, like the HYE, requires direct elicitation for many specific health profiles, and thus faces the same implementation difficulties. Index values for SAVEs are not available in the research literature and, as with PTO values more generally, the reliability of the technique has not been determined.
We take up the issue of societal values and QALYs again in Chapter 4, where we examine the ethical assumptions embedded in the QALY metric and strategies for addressing distributive and other ethical issues that arise in regulatory CEAs that employ QALYs.
The QALY is the obvious choice at this time for standardizing regulatory analysis on a single HALY metric. Researchers have completed only limited work using the HYE and the SAVE, and health state values using these metrics are not readily available. Furthermore, values for the wide range of health conditions considered in regulatory analysis are not likely to be developed in the near term using these approaches, given the complexities of establishing values (such as conditioning health state values on duration or transitions from prior health states) and the expense of related research. The HYE, while in theory superior to the QALY as a measure of preferences for health, would require a significantly more complex elicitation process, as would the SAVE, which is valued using variants of the PTO method. The DALY can be valued using a variety of methods consistent with QALY measurement. However, the inversion of the calculations, as losses averted from some normative life expectancy, introduces opportunities for confusion in interpretation if other results are presented as QALY gains.
Alternatives to the QALY have not undergone extensive reliability evaluation. Although the QALY can be criticized for not adhering to expected utility theory or for ignoring certain dimensions of societal values for health-related improvements such as severity or threat to life, it is feasible and widely used. In addition, the QALY is supported by a number of generic, multiattribute HRQL survey instruments and can be estimated for health endpoints in regulatory analysis using a variety of approaches.