Comparative Effectiveness of Mandates and Financial Policies Targeting COVID-19 Vaccine Hesitancy: A Randomized, Controlled Experiment

Experts debate whether COVID-19 vaccine mandates or financial incentives will “backfire” psychologically by reducing interest in vaccination. Among 3,698 unvaccinated U.S. residents, we conducted a randomized, controlled survey-embedded experiment to estimate the absolute and relative psychological effects of: mandates by employers or airlines, bars, and restaurants; lotteries for $1 million, $200,000, or $100,000; guaranteed cash for $1000, $200, or $100; and $1,000 as either a tax credit or penalty. Vaccine intention--the study outcome—predicts uptake and provides insight into the psychological mechanism. Compared to controls, those who learned about the $1,000 cash reward were 17.1 (±5.3)% more likely to want vaccination. Employer mandates are more promising than other mandates (8.6 [+/- 7.4]% vs. 1.4 [+/- 6.0]%). The full results suggest that neither mandates nor financial incentives are likely to have counterproductive psychological effects. These policies are not mutually exclusive and, if implemented well, they may increase vaccine uptake.