Social Vulnerability Index (SVI) The Social Vulnerability Index is a place based index, database, and interactive mapping tool that quantifies how social factors influence a community s capacity to prepare for, respond to, and recover from public health emergencies, natural disasters, or environmental hazards. The index was created by the U.S. Centers for Disease Control and Prevention (CDC) in partnership with the Agency for Toxic Substances and Disease Registry (ATSDR), specifically its Geospatial Research, Analysis Services Program (GRASP). The dataset contains 15 U.S. Census derived variables grouped into four thematic domains socioeconomic status, household composition, minority status, and housing/transportation. For each census tract (as well as ZIP Code Tabulation Areas and counties), the SVI provides raw percentile ranks, a composite score (0 1), and flag values that identify the top 10 % of tracts as highly vulnerable. Updated every two years after the American Community Survey release, the index is downloadable as CSV files and displayed via a web based map. Primary uses include guiding emergency management planning, allocating resources for disaster mitigation, informing health equity research, and supporting environmental justice assessments. Unique features are its dual national and state specific ranking options, the ability to drill down to fine grained geographic units, and its integration of a transparent data dictionary that details variable sources and calculation methods.