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Gold Bars for Vaccination: Evaluating the Efficacy of Vaccine Lotteries

Updated: Jun 28, 2022

By: Megan Yeo

The rapid production of the Covid-19 vaccine seemed to promise a turning point in the global pandemic. A key obstacle, however, remained – convincing people who were medically eligible to take the vaccine. As vaccine skepticism rose, vaccination rates in parts of the U.S., for instance, remained well below the national average, with some regions only managing to vaccinate about half of their adult population. Across the globe, governments have implemented a host of measures to encourage vaccine take-up, ranging from lotteries to collaborations with dating apps, with varied success. It is clear that traditional economic models of decision-making may not fully explain vaccine uptake trends. This article thus aims to examine the effectiveness of government measures to promote vaccine uptake through the lens of behavioral economics, particularly evaluating the effectiveness of lotteries as a means of incentivizing vaccination.

In order to promote the uptake of Covid-19 vaccines, many governments have turned to holding lotteries. Prizes have spanned a large range of items. In Hong Kong, for instance, the government offered an apartment worth $1.4 million USD, gold bars, and a $100,000 USD shopping spree as the grand prizes of the draw. The rationale behind vaccine lotteries was simple: the benefits of taking a vaccine are often intangible, but providing rewards, which are often monetary in nature, provides a strong, material incentive for individuals, shifting an individual’s cost-benefit analysis in favor of taking vaccines. Behavioral scientists and economists further suggest that despite the extremely minute chance of actually winning a prize, people tend to overestimate their chance of winning the lottery and hesitate to pass up the chance to do so, hence making lotteries particularly effective.

Notably, Philadelphia’s vaccine lottery was designed based on insights from behavioral economics. It is based on the theory of loss aversion first identified by behavioral economists Kahneman and Tversky, which holds that individuals feel a greater psychological effect from losses as compared to gains. In Philadelphia’s lottery, everyone was thus automatically enrolled, but would only have a chance of winning if they were vaccinated, meaning unvaccinated individuals “lost” their chance to win. Loss aversion would hence incentivize more people to get vaccinated.

Nevertheless, though it seems natural that lotteries would be successful in moving the needle, results were mixed. A recent studyanalyzing 19 states in the U.S. found that lotteries were ineffective in promoting vaccination, as “[e]stimates of the association between an announcement and vaccination rates were very small in magnitude and statistically indistinguishable from zero.” In Alberta, Canada, researchers also found that lotteries had a limited impact on vaccine uptake. Researchers have offered possible reasons for this: some suggested that counterintuitively, lotteries could have exacerbated vaccine skepticism. Perceptions that the vaccines are unsafe could be inadvertently reinforced by the fact that money was being offered to convince skeptics to vaccinate.

Nevertheless, even if lotteries were effective in the short term, we may question whether lotteries are truly a viable solution for the long term. Lotteries are merely a short-term solution as they appeal to extrinsic motivation for a reward rather than intrinsic motivation: once the monetary incentive is no longer present, people may no longer be motivated to take vaccines. Worse still, it is possible that monetary incentives could even undermine intrinsic motivation; behavioral economist Dan Ariely argues, for instance, that introducing market norms into contexts normally governed by social norms can undermine the latter, leading to negative effects in the longer term. In this case, attaching vaccines to financial benefits could undermine the motivation to get vaccinated out of a sense of responsibility to one’s community.

Ultimately, to truly promote vaccine take-up in the short and long term, measures must be taken to address the deeper issues that cause vaccine hesitancy. With numerous conspiracy theories regarding the harms of vaccination being circulated, misinformation is a clear issue. Information campaigns to debunk these conspiracies seem like the natural answer, but they too must be implemented with caution. Choi and Saleska, for instance, highlight that confirmation bias–the tendency for humans to only consider evidence which support their own beliefs–is a key reason for the rampant spread of misinformation. Information campaigns could inadvertently reinforce the saliency of conspiracy theories, confirming harmful beliefs. Thus, in implementing measures to curb vaccine hesitancy, governments should consider the underlying cognitive biases that may influence their success.


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