Personalized Letters And Emails Increased Marketplace Enrollment Among Households Eligible For Zero-Premium Plans

More than one million low-income uninsured people are eligible for zero-premium cost-sharing reduction (CSR) silver plans through the Affordable Care Act (ACA) Marketplaces. However, many are not aware of these options, and Marketplaces are uncertain about what types of informational messages will increase take-up. In 2021 and 2022, before and after the introduction of zero-premium plans in Covered California, California's individual ACA Marketplace, we conducted two randomized controlled trials among low-income households that submitted an application and were found eligible for $1 per month or zero-premium coverage but were not yet enrolled. We tested the effect of personalized letters and emails that informed households that they were eligible for a $1 per month or zero-premium CSR silver plan. Across both settings, low-cost personalized outreach increased rates of ACA enrollment, CSR silver plan take-up, and $1 per month or zero-premium CSR silver plan take-up. But even with free or nearly free coverage options, absolute rates of enrollment remained low, suggesting that more resource-intensive efforts are needed to help prospective enrollees overcome nonprice barriers.