What is Social Vulnerability?

Every community must prepare for and respond to hazardous events, whether a natural disaster like a tornado or disease outbreak, or a human-made event such as a harmful chemical spill. A number of factors, including poverty, lack of access to
transportation, and crowded housing may weaken a community’s ability to prevent human suffering and financial loss in a disaster.

These factors are known as social vulnerability

What is the CDC/ATSDR Social Vulnerability Index?

ATSDR’s Geospatial Research, Analysis & Services Program (GRASP) created databases to help emergency
response planners and public health officials identify and map communities that will most likely need
support before, during, and after a hazardous event.

The CDC/ATSDR SVI uses U.S. Census data to determine the social vulnerability of every census tract. Census
tracts are subdivisions of counties for which the Census collects statistical data. The SVI ranks each tract on
16 social factors, including poverty, lack of vehicle access, and crowded housing, and groups them into four
related themes. Maps of the four themes are shown in the figure below. Each tract receives a separate
ranking for each of the four themes, as well as an overall ranking.

Hurricane Sandy ‐ Breezy Point, NY

Hurricane Sandy ‐ Breezy Point, NY Photographer – Pauline Tran

Range of vulnerability in FultonCounty, Georgia.

Maps show the range of vulnerability in Fulton County, Georgia for the four themes

How Can the CDC/ATSDR SVI Help Communities be Better Prepared?

  • Estimate the amount of needed supplies like food, water, medicine, and bedding.
  • Help decide how many emergency personnel are required to assist people.
  • Identify areas in need of emergency shelters.
  • Plan the best way to evacuate people, accounting for those who have special needs, such as people without vehicles, the elderly, or people who do not understand English well.
  • Identify communities that will need extra funding and support before, during, and after a disaster.

For more information, visit or contact the SVI Coordinator (