Comparing The Effects Of Nudges And Automatic Plan Switching On Choice Errors Among Low-Income Marketplace Enrollees

During the 2022 open enrollment period in California's Affordable Care Act Marketplace, we tested two interventions designed to reduce choice errors among low-income households enrolled in bronze plans that were eligible for zero-premium cost-sharing reduction (CSR) silver plans with more generous benefits. A randomized controlled trial nudge intervention used letter and email reminders to encourage consumers to switch plans, and a quasi-experimental crosswalk intervention automatically enrolled eligible households from bronze plans into zero-premium CSR silver plans with the same insurers and provider networks. The nudge intervention led to a statistically significant 2.3-percentage-point (26 percent) increase in CSR silver plan take-up relative to the control group, but nearly 90 percent of households remained in nonsilver plans. The automatic crosswalk intervention resulted in an 83.0-percentage-point (822 percent) increase in CSR silver plan take-up compared with the control group, with more than 90 percent of households enrolled in CSR silver plans. Our findings can inform health policy debates on the relative effectiveness of different approaches to reducing choice errors among low-income households in the Affordable Care Act Marketplaces.