Social vulnerability metrics are increasing in sophistication and usage in both research and practice. Among the best known is the Social Vulnerability Index (SoVI®), a metric that permits comparisons of places (block groups, census tracts, metropolitan areas, counties) (Cutter et al., 2003; Box 4.2). Mapping SoVI® scores illustrates the extremes of social vulnerability—those places with very high values (the most vulnerable), and those with relatively low values (the least vulnerable) (Figure 4.2). SoVI® captures the multidimensional nature of social vulnerability—vulnerability that exists prior to any hazard or disaster event. In addition to describing the relative level of social vulnerability, the metric also enables the examination of those underlying dimensions that are contributing to the overall score such as age disparities, socioeconomic status, employment, and special-needs populations.
FIGURE 4.2 Social Vulnerability Index, 2006-2010. Areas in red denote higher levels of social vulnerability relative to other counties, whereas counties in blue show lower levels of social vulnerability. Mapping by standard deviations (represented here as top and bottom 20 percent) shows the extremes of the distribution, which is of greatest interest. HVRI = Hazard and Vulnerability Research Institute. Source: S. Cutter/HVRI.