On the basis of data from many nations, our forthcoming book asks and answers a question pressing in democratic and nondemocratic nations alike: What do citizens actually think about behaviorally informed policies?

We apply a novel crowdsourcing approach to provide rapid insights on the most promising interventions to promote uptake of COVID-19 booster vaccines. In the first stage, international experts proposed 46 unique interventions. To reduce noise and potential bias, in the second stage, experts and...