experts, “… a variant of QALYs which have been standardized for comparative [international] use” (Murray and Acharya, 1997, p. 704).
The DALY construct reflected two much-criticized analytical choices that are no longer considered essential for the measure. First, decrements in longevity were calculated from a worldwide optimum life expectancy, represented by that of Japanese women (82.5 years). The second distinctive feature was age weighting. Years lived in young adulthood were given a greater value in comparison to years lived earliest and at the end of the life span. Age weighting gives priority to the potential for improving health outcomes among the members of society most critical to the well-being of society as a whole, those in their productive years of life.
Age weighting and the use of optimum life expectancy are not, however, in principle necessary to the DALY construct. DALY weights may be determined based on any of the methods described earlier in this chapter, including PTO, SG, TTO, or RS. Some more recent applications of DALYs are not age weighted, use life tables for the actual target population, and apply DALY weights derived from sources based on different methods (see, e.g., de Hollander et al., 1999; Fox-Rushby and Hanson, 2001, for applications and discussion of analytic options using DALYs).
QALYs and other individually based preference or utility measures are deemed by some to be inappropriate for societal resource allocation decisions. These measures do not adequately account for the value attached to saving lives relative to improving health or to the priority that may be given to improving outcomes for the most severely impaired, regardless of the size of the improvement. QALYs measure only the size of an improvement in health and disregard health state starting and endpoints. This reflects the irrelevance, in the calculation of QALY gains or losses, of all personal attributes except the quality adjustment to a life year and the number of aggregate QALYs. However, in surveys of people’s preferences for public investments in health, their “health-related social welfare function” is rarely consistent with QALY maximization (Ubel et al., 1996; Menzel, 1999).
Nord (1992, 1999) has proposed several strategies to incorporate this concern for severity and life saving in HALY measurement. One of these approaches, related to the PTO valuation method described earlier, selects a single health care outcome as the common unit of measurement for all health-related outcomes. The common unit Nord proposes is the SAVE, the value of saving the life of a young person and restoring him to full health. To determine the relative societal value of a given health outcome, two equally expensive programs are compared. One program saves a young life each year and the other produces n health outcomes of type x each year.