Abstract
The socioeconomic status (SES) component of the Social Vulnerability Index ranks US counties based on the SES of county residents and was used to evaluate the impact of SES on the performance of the health care delivery system. Using Medicare fee-for-service data, the performance of the health care delivery system was evaluated based on population measures such as per capita hospital admissions, quality of care measures such as surgical mortality, postacute care measures such as readmissions, and service volume measures such as posthospitalization nursing home and rehabilitation admissions. Substantial differences in delivery system performance across SES populations were observed.