Hazards & Vulnerability Research Institute (HVRI)


 

Social Vulnerability Index | Frequently Asked Questions

What is Social Vulnerability?

What Population Characteristics Affect Vulnerability?

What Data Sources Were Used in the Creation of SoVI©?

What is the Social Vulnerability Index (SoVI©)?

How is Social Vulnerability Represented as a Number?

How is the Social Vulnerability Index Classified and Displayed?

 

What is Social Vulnerability?

Generally defined, vulnerability is the potential for loss of life or property due to hazards. The hazards-of-place model (Cutter 1996) combines the biophysical vulnerability (physical characteristics of hazards and environment) and social vulnerability to determine an overall place vulnerability. Social vulnerability is represented as the social, economic, demographic, and housing characteristics that influence a community’s ability to respond to, cope with, recover from, and adapt to environmental hazards.

[Top]



What Population Characteristics Affect Vulnerability?

Socioeconomic Status (Income, Political Power, Prestige): Socioeconomic status affects the ability of a community to absorb losses and be resilient to hazard impacts. Wealth enables communities to absorb and recover from losses more quickly using insurance, social safety nets, and entitlement programs.

High status (-) Low income or status (+)

Gender: Women often have a more difficult time during recovery than men because of sector-specific employment (e.g., personal services), lower wages, and family care responsibilities.

Gender (+)

Race and ethnicity: These factors impose language and cultural barriers and affect access to post-disaster funding and occupation of high-hazard areas.

Non-white (+) Non-Anglo (+)

Age: Extremes of age affect the movement out of harm’s way. Parents lose time and money caring for children when day care facilities are affected; the elderly may have mobility constraints or concerns that increase the burden of care and lack of resilience.

Elderly (+) Children (+)

Employment loss: The potential loss of additional employment following a disaster increases the possible number of unemployed workers in a community. Such losses contribute to a slower recovery from the disaster.

Unemployment (+)

Rural/Urban: Rural residents may be more vulnerable because of lower incomes and more dependence on a locally based resource economy (e.g., farming or fishing). High-density areas (urban) complicate evacuation out of harm’s way.

Rural (+) Urban (+)

Residential property: The value, quality, and density of residential construction affect potential losses and recovery. Expensive homes on the coast are costly to replace, mobile homes are easily destroyed and less resilient to hazards.

Mobile homes (+)

Renters: People rent because they are transients, do not have the financial resources for home ownership, or do not want the responsibility of home ownership. They often lack access to information about financial aid during recovery. In extreme cases, renters lack sufficient shelter options when lodging becomes uninhabitable or too costly to afford.

Renters (+)

Occupation: Some occupations, especially those characterized as primary extractive industries, may be severely affected by a hazard event. Self-employed fishermen suffer when their means of production is lost, and they may not have the requisite capital to resume work in a timely fashion; therefore, they may seek alternative employment. Migrant workers engaged in agriculture and low-skilled service jobs (housekeeping, child care, and gardening) may suffer similarly as disposable income fades and the need for services declines. Immigration status also affects occupational recovery.

Professional or managerial (-) Clerical or laborer (+) Service sector (+)

Family structure:Families with large numbers of dependents and single-parent households often have limited wherewithal to outsource care for dependents and thus must juggle work responsibilities and care for family members. All these factors affect resilience to and recovery from hazards.

Large families (+) Single-parent households (+)

Education: Education is linked to socioeconomic status in that higher educational attainment affects lifetime earnings, and limited education constrains the ability to understand warning information and access recovery information.

Little education (+) Highly educated (-)

Medical Services: Health care providers, including physicians, are important post-event sources of relief. The lack of proximate medical services lengthens the time needed to obtain short-term relief and achieve longer-term recovery from disasters. Hospitals and nursing homes represent an increase in socially vulnerable people as the residing populations are less able to independently cope with disasters.

Higher density of medical (-), nursing homes (+), hospitals (+)

Social dependence: People who are totally dependent on social services for survival are already economically and socially marginalized and require additional support in the post-disaster period.

High dependence (+) Low dependence (-)

Special-needs population: Special-needs populations (infirm, institutionalized, transient, homeless) are difficult to identify, let alone measure and monitor. Yet it is this segment of society that invariably is left out of recovery efforts, largely because of this invisibility in communities.

Large number of special needs (+) Small number of special needs (-)


Heinz Center, 2002. Human Links to Coastal Disasters . Washington D. C.: The H. John Heinz III Center for Science, Economics and the Environment

[Top]



What Data Sources Were Used in the Creation of SoVI©?

The majority of the sources used by the Hazards Research Lab are obtained from the five-year American Community Survey estimates compiled by the U.S. Census Bureau. Data are also obtained from the 2007 one-year American Community Survey, the Geographic Names and Information System (GNIS), and model-based Small Area Health Insurance Estimates (SAHIE) published by the U.S Census Bureau, Data variables are used to represent the population characteristics that affect social vulnerability (See list above). For instance, the number of people older than 65 and the number of people under 5 years old were used to represent the socially vulnerable population due to age.

[Top]



What is the Social Vulnerability Index (SoVI©)?

County-level socioeconomic and demographic data were used to construct an index of social vulnerability to environmental hazards, called the Social Vulnerability Index (SoVI©) for the United States based on data collected from 2005 to 2009. The SoVI© methodology and results was originally published in the following article:

Cutter, S.L., B.J. Boruff, and W.L. Shirley. 2003. “Social Vulnerability to Environmental Hazards.” Social Science Quarterly 84(2): 242-261.

[Top]



How is Social Vulnerability Represented as a Number?

After obtaining the relevant data, a principle components analysis is used to reduce the data into set of components. Slight adjustments are made to the components to ensure that the sign of the component loadings coincide with each individual population characteristic’s influence on vulnerability. All components are added together to determine a numerical value that represents the social vulnerability for each county.

[Top]



How is the Social Vulnerability Index Classified and Displayed?

The SoVI® was created as a comparative index at a county-level for the entire United States. Therefore, the SoVI® scores need to be displayed in relation to each other. Generally, the SoVI® is classified using standard deviations. Social vulnerability scores that are greater than 2 standard deviations above the mean are considered the most socially vulnerable, and scores below 2 standard deviations less than the mean are the least vulnerable.

[Top]