Nice. 

By the way how does this compare to the results of "Monetary incentives increase COVID-19 vaccinations" (Campos-Mercade et al)? Seems like the results here involved a similar sized incentive, but had larger effects?

Valuing vaccination

Using money as a motivation for the public to get vaccinated is controversial and has had mixed results in studies, few of which have been randomized trials. To test the effect of money as an incentive to obtain a vaccine, Campos-Mercade et al. set up a study in Sweden in 2021, when various age groups were first made eligible to receive the severe acute respiratory coronavirus 2 vaccine (see the Perspective by Jecker). The effect of a small cash reward, around US $24, was compared with the effect of several behavioral nudges. The outcome of this preregistered, randomized clinical trial was that money had the power to increase participation by about 4 percentage points. Nudging and reminding didn’t seem to be deleterious and even had a small positive effect. Of course, the question of whether it is ethical to pay people to be vaccinated like this needs to be addressed. —CA

Abstract

The stalling of COVID-19 vaccination rates threatens public health. To increase vaccination rates, governments across the world are considering the use of monetary incentives. Here we present evidence about the effect of guaranteed payments on COVID-19 vaccination uptake. We ran a large preregistered randomized controlled trial (with 8286 participants) in Sweden and linked the data to population-wide administrative vaccination records. We found that modest monetary payments of 24 US dollars (200 Swedish kronor) increased vaccination rates by 4.2 percentage points (P = 0.005), from a baseline rate of 71.6%. By contrast, behavioral nudges increased stated intentions to become vaccinated but had only small and not statistically significant impacts on vaccination rates. The results highlight the potential of modest monetary incentives to raise vaccination rates.