Taking Stock: Gains in Health Insurance Coverage under the ACA as of March 2015

Since the ACA’s first open enrollment period began in late 2013, there has been rapid enrollment growth in Medicaid and in private health insurance plans purchased through the new Marketplaces. However, administrative data on Medicaid enrollment and enrollment in Marketplace health plans do not show how health insurance coverage is changing under the ACA, because not all of those enrolling were previously uninsured. Household survey data are needed to track changes over time in the share of the population that is uninsured. This report uses the Urban Institute’s Health Reform Monitoring Survey (HRMS) to examine trends in health insurance coverage since the first quarter of 2013. According to HRMS data, the uninsurance rate among nonelderly adults has declined 7.5 percentage points between September 2013 and March 2015, representing 15 million fewer adults without health insurance.