California's early ACA expansion increased coverage and reduced out-of-pocket spending for the state's low-income population

The Affordable Care Act (ACA) expanded eligibility for Medicaid to millions of low-income adults. While many expanding states implemented their expansion in 2014, five states and the District of Columbia expanded eligibility as early as 2010 by taking advantage of provisions in the ACA and Medicaid waivers. We used restricted data from the National Health Interview Survey to examine the impact of California's Low Income Health Program, an early expansion program that began in 2011. Our study demonstrates that the county-by-county rollout of expanded public insurance coverage in California significantly increased coverage, by 7 percentage points, and significantly reduced the likelihood of any family out-of-pocket medical spending in the previous year, by 10 percentage points, among low-income adults.