Lottery Incentive Nudges to Increase Influenza Vaccinations

Overview

In the current study, the study team will explore whether small incentives are effective at promoting flu vaccine uptake. The study is designed to compare the relative efficacy of incentives of equal perceived expected value (EV) or equal implementation costs, to assess whether people are more likely to get vaccinated in response to lotteries with very high payoffs than to small certain cash payout or slightly higher-probability, more moderate payoffs. In particular, given the potential appeal of official state lottery tickets, one study arm will receive a Pennsylvania scratch-off lottery ticket for getting a flu vaccine. A primary hypothesis is that lotteries will outperform simple reminders (encouraging respondents to get the flu shot at their upcoming appointment) and the standard of care, representing the ambient healthcare system and public health campaigns to increase vaccination.

During the 2021-22 flu season, the study team will contact Geisinger patients who have a primary care or specialist appointment scheduled during flu season and encourage them to get a flu shot. Patients will be randomized into 4 to 9 study arms, depending on a sample size projection completed in August 2021. Arms will test the relative efficacy of a variety of small monetary incentives on flu shot uptake. Incentives may include (a) a $1 Pennsylvania scratch-off lottery ticket (with top prize of $5,000), (b) $1 in cash, (c) entry into a raffle for $5,000 absent upfront odds, (d) entry into a raffle for $5,000, with 1-in-5,000 odds of winning, (d) entry into a raffle for $50, with 1-in-50 odds of winning, and (e) entry into a raffle for $500, with 1-in-500 odds of winning. There will be one no-contact control arm and at least 1 reminder control arm (with additional control arms added given sufficient sample size and additional message versions to be tested). Included in the study will be current Geisinger patients 18+ years of age with no contraindications for flu vaccine who have an appointment scheduled during the study period with a provider who can administer the vaccine. The primary study outcomes will be the rates of flu vaccination and flu diagnosis during the 2021-22 season by targeted patients.