Can People be “Nudged” into Getting Vaccinated?

In Economics, Chapter 10, Section 10.4, when discussing behavioral economics, we mentioned Richard Thaler’s idea of nudges, which are small changes that government policymakers or business managers can make that may affect people’s behavior. Underlying the concept of nudges is the assumption that at least some of the time people may not be making fully rational decisions (We discuss in the chapter the reasons why people may not always make fully rational decisions.)  An example of a nudge is a business automatically enrolling employees into retirement savings plans to overcome the tendency of many people to be unrealistic about their future behavior. 

Once vaccines for the Covid-19 virus became widely available to the general adult population in 2021, some government policymakers were concerned that not enough people were being vaccinated to quickly curb the pandemic. Some people who declined to be vaccinated had carefully thought through the decision and declined the vaccine either because they believed they were at only a small risk of developing a severe case of Covid-19 or for other reasons. But some people who were not vaccinated intended eventually to receive the injection but for various reasons had not yet done so. The second group were potentially candidates for being nudged into becoming vaccinated.

A recent National Bureau of Economic Research working paper by Tom Chang of the University of Southern California and colleagues reports an experiment that measured the effect of nudges intended to increase the likelihood of someone becoming vaccinated.  The study was conducted in Contra Costa Country in northern California with 2,700 Medicaid (a state run system of health care offered to people with low incomes) recipients who agreed to participate. The study took place between May and July 2021 after all adults in the county had been eligible for several weeks to receive a vaccine. Half the people involved in the experiment received three nudges:  1) a video noting the positive effects of being vaccinated, 2) a financial incentive of either $10 or $50 if they received a vaccination within two weeks, and 3) “a highlighted convenient link to the county’s new public vaccination appointment scheduling system or just a message about getting vaccinated without a link.” The other half of the people involved in the experiment received none of these nudges.

The authors’ statistical analysis of the results of the experiment indicates that none of the nudges individually or in combination significantly raised vaccination rates. Do these results show conclusively that nudges are ineffective in increasing Covid-19 vaccination rates? The authors note that the people involved in this experiment were not representative of the U.S. population. All had low incomes (which made them eligible for Medicaid), they were relatively young, and were more likely to be Black or Hispanic than is true of the overall U.S. population. The study also took place just before the peak in the spread of the Delta variant of Covid-19 at a time when infection rates appeared to be declining. So, while for these reasons the study cannot be called a definitive, it does provide some evidence that nudges may not be effective in changing behavior towards vaccinations. 

Source: Tom Chang, Mireille Jacobson, Manisha Shah, Rajiv Pramanik, and Samir B. Shah, “Financial Incentives and other Nudges Do Not Increase Covid-19 Vaccinations among the Vaccine Hesitant,” National Bureau of Economic Research, Working Paper 29403, October 2021.