Source: <u>http://icd9cm.chrisendres.com/index.php?action=child&recordid=8185</u> , - - <u>http://en.wikipedia.org/wiki/List_of_ICD 9_codes_800 999:_Injury_and_poisoning</u> The AIS classification scheme describes injuries by body region (one digit), type of anatomic structure (one digit), specific anatomic structure (two digits), and level (two digits). The seventh digit describes the threat to life associated with the injury. This ranges from 1 (Minor Injury) to 6 (Immediately Fatal).<sup>9</sup> The last digit is often referred to as the AIS code. When multiple injuries occur it is common to record the maximum AIS code (MAIS), as is done in classifying road traffic injuries in the US and elsewhere. As will be seen below, estimates of injury costs are often classified by AIS code (i.e., the threat-to-life code), as well as by body part and the nature of the injury (Zaloshnja et al., 2004).

Injuries associated with disasters are studied in the epidemiological literature, which provides information on diagnoses of past injuries. The issue for benefit-cost analysis is at what level of detail injuries avoided by disaster risk management projects can be predicted. In the US, injuries associated with earthquakes, floods and hurricanes are predicted by FEMA’s HAZUS model. The model estimates injuries by location, time of day, and population group. The nature of the injury is, however, limited to a four-point severity scale, where 1= minor or moderate injury (AIS 1 or 2); 2 = serious injury (AIS 3); 3 = severe or critical injuries (AIS 4 or 5); and 4 = fatal injury. Section V explores the consequences for valuation of having limited information about the nature of injuries.

# III. Benefit-Cost Analyses of Measures to Reduce Disaster Losses

Key measures to reduce losses in the event of a disaster include the strengthening of building to withstand shaking and prevent collapse in the event of an earthquake and early warning systems for floods and hurricanes. To judge whether these projects are efficient, benefit-cost analyses are typically conducted. This section describes the framework of probabilistic benefit-cost analysis, in order to describe how valuation of avoided death and injury may be incorporated into the analysis. This is followed by examples of studies where including avoided deaths as a benefit has significantly altered the benefit-cost results.

An alternate approach (World Bank, 2000) to evaluating the efficiency of projects is costeffectiveness analysis. Cost-effectiveness analysis calculates the present discounted value of project costs net of non-health benefits (e.g., property losses avoided) and divides these by the reduction in fatal and non-fatal injury, measured by QALYs (or DALYs).<sup>10</sup> The cost per QALY or DALY avoided may then be compared to other projects. Ultimately, however, a value must be placed on a QALY or DALY to determine if the project is efficient.

> 9 The categories are: (1) minor injury; (2) moderate injury; (3) serious injury; (4) severe injury; (5) critical injury; (6) immediately fatal (AAAM 1990).

> 10 A disability-adjusted life year (DALY) describe the fraction of a life year lost to an illness or injury.

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