total costs of injury (by MAIS) relative to the cost of a fatality. Using US data as reported in Robinson (2007), an MAIS 5 injury is equivalent to 0.71 lives lost and an MAIS 4 injury equivalent to 0.22 lives lost. This provides a quick-and-dirty method of approximating the importance of avoided injuries, given estimates of the VSL.

It is also possible to use estimates of QALY losses associated with categories of injury to approximate injury costs. QALY losses could be associated with MAIS code, or they could be associated with specific types of injuries (e.g., skull fractures, crush injuries) if the number of injuries avoided can be estimated in this way. Mappings from MAIS category to QALYs lost are available in the US, based on road traffic injuries (Spicer and Miller, 2008). Mappings from injuries, classified by ICD-9 code, to QALYs also exist for the US (Miller et al., 1995; Segui-Gomez and MacKenzie, 2003). The Appendix contains WHO figures on DALY losses associated with various categories of injury. Although there are theoretical reasons why QALYs should not be monetized using the Value of a Statistical Life Year (VSLY), the use of the VSLY should provide order-ofmagnitude estimates of the value of QALY losses. QALY losses across injury categories explain 97% of the variation in total injury costs for road traffic injuries in the US (Zaloshnja, et al., 2004). However, QALY losses are only about 60% of total costs of road traffic injuries. This suggests that monetizing QALY losses will provide a lower bound estimate to the value of injury.

The methods suggested above will provide order of magnitude estimates of the value of avoided death and injury associated with disaster risk reduction projects. If these benefits are significant, a more careful, bottom-up analysis may be warranted. The methods presented in this paper should, however, allow analysts to determine whether inclusion of avoided death and injury will enable a disaster risk reduction project to pass the benefitcost test.

# B. Concluding Thoughts

Benefit-cost analysis is an important tool for evaluating the efficiency of disaster risk reduction policies, as well as policies in other sectors. Efficiency is, of course, only one criterion by which policies are judged, but it is an important one—especially when resources are scarce. We note that cost-effectiveness analysis is another approach that can, and should, be used in evaluating disaster risk reduction policies. When reductions in injury and death are an important component of project benefits, it makes sense to calculate the reduction in injuries and deaths in terms of QALYs (or DALYs). The costs of the project, minus the non-health benefits of the project, can then be divided by the QALYs saved to calculate a cost per QALY avoided.<sup>42</sup> One advantage of cost-effectiveness analysis is that it is easy to compare the cost per QALY across policies—across policies to reduce disaster risks and across health and safety policies in various sectors—to encourage consistency in decision-making. To achieve the same consistency in benefit-cost analyses, it is imperative that a consistent

> 42 The saving in medical costs should also be subtracted from project costs before calculating the cost per QALY (see Gold et al., 1996 and Miller et al., 2006).

30