One push and go

Publish date 27-06-2022

by Pierluigi Conzo

In one study, strategies for improving one's own well-being and that of the whole society

The term nudge generally refers to small "pushes" given to people so that they implement sustainable behaviors for themselves and for society. As detailed in previous articles, there are many reasons why individuals, although recognizing the importance of certain choices or behaviors for their own well-being and that of society, are unable to make them happen. These reasons reside in the imperfect rationality of human nature, which subjects us, more often than not, to "cognitive distortions" deriving from emotions (for example, fear of regret, preference for the status quo, inertia, aversion to losses ...) or from a specific context that characterizes the choice (for example number and order of choice options).

A recent study published in a prestigious scientific journal, PNAS, analyzes the impact of a nudging policy aimed at stimulating the vaccination rate for normal seasonal flu in the United States. These are text messages sent as a reminder to about 700,000 patients in pharmacies linked to the American giant Walmart. These patients were randomly divided into 22 groups, to which a different message was sent; another group of patients - used as a comparison group - did not receive any messages. Additionally, some patients received the message on the same day, while other patients received the messages on two different days. The structure of this intervention therefore allowed the authors to identify what was the content of the message and the most effective sending frequency to "push" people to go to the pharmacy to get vaccinated.

The content of the messages used is varied: some are based on humor, in an attempt to increase the "memorability" of the message ("Did you hear the joke about the flu? It doesn't matter, we don't want to spread it"); another announced that vaccination was now a consolidated and growing social practice, leveraging social confrontation as a "push" to conform to the behavior of others ("More Americans than ever are now vaccinating themselves against the flu"); yet another leveraged the fact that asking people to commit to doing something can act as a stimulus in itself ("If you're going to get a flu shot at Walmart, get involved by responding with a message: I'll get a flu shot" ).

The results of this nudging intervention suggest that, when compared to the control condition, the most effective message generated a 2.9 percentage point increase in flu shots at Walmart - an increase of about 10%!

The most effective messages were two: "It's flu season and you can get a flu shot at Walmart." The second message arrived 72 hours later and reminded patients, "A flu shot is waiting for you at Walmart." Importantly, all 22 messages significantly increased vaccination rates relative to the control condition, and did so by an average of 2.1 percentage points (an increase of approximately 9%).

In general, there are two characteristics of the content of the message that seem to increase its effectiveness: its inconsistency with the typical communications that users receive from the pharmacy (interrogative, imperative and generally negative tone) and its acting as a "reminder", implicitly suggesting that the decision to get the vaccine had already been made and that the vaccine was waiting for them.

Although the result of interventions aimed at encouraging generic flu vaccinations, the results of this study suggest how a simple (and inexpensive) nudging policy, based on sending text messages and reminders, can be of great help in the vaccination campaign against Covid-19.


There are many reasons why, despite recognizing the importance of certain choices or behaviors, many individuals fail to make them

Pierluigi Conzo

NP Marzo 2022

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