Behavioral Nudges Increase COVID-19 Vaccinations: Two Randomized Controlled Trials

102 Pages Posted: 5 Apr 2021 Last revised: 4 Jun 2021

See all articles by Hengchen Dai

Hengchen Dai

University of California, Los Angeles (UCLA) - Anderson School of Management

Silvia Saccardo

Carnegie Mellon University, Department of Social and Decision Sciences

Maria Han

University of California, Los Angeles (UCLA) - UCLA Health System

Lily Roh

University of California, Los Angeles (UCLA) - UCLA Health System

Naveen Raja

University of California, Los Angeles (UCLA) - UCLA Health System

Sitaram Vangala

University of California, Los Angeles (UCLA) - UCLA Health System

Hardikkumar Modi

University of California, Los Angeles (UCLA) - UCLA Health System

Shital Pandya

University of California, Los Angeles (UCLA) - UCLA Health System

Michael Sloyan

University of California, Los Angeles (UCLA) - UCLA Health System

Daniel Croymans

University of California, Los Angeles (UCLA) - UCLA Health System

Date Written: June 1, 2021

Abstract

Ending the COVID-19 pandemic requires quick and effective strategies to overcome citizens’ reluctance and failure to get vaccinated (1,2). We present two sequential randomized controlled trials (RCTs) that tackle this challenge with behavioral science insights. We deliver a popular nudge—text-based reminders that make vaccination salient and easy—to patients of a large healthcare system one day (first RCT; N=93,354) and eight days (second RCT; N=67,092) after they receive notification of vaccine eligibility. The first reminder boosts appointment and vaccination rates within the healthcare system by 6.07 (or 84%) and 3.57 (or 26%) percentage points, respectively. Adding to reminders language that makes patients feel the vaccine is already theirs boosts appointment and vaccination rates by an additional 1.49 and 1.07 percentage points, respectively, relative to reminders without such language. However, combining reminders with an information intervention addressing vaccine hesitancy yields no additional benefits. Online studies (N=3,181) examining how the first RCT’s reminders affect vaccination intentions reveal divergent patterns, underscoring the importance of pilot-testing interventions in the real world. The second reminder produces a small yet statistically significant boost in appointment and vaccination rates within the healthcare system (1.65 and 1.06 percentage points, respectively) among those who failed to act after the first reminder. These findings provide evidence for scalable behavioral nudges that can promote COVID-19 vaccinations at almost zero marginal cost.

Note: *The first two authors contributed equally to this work. Trial Registration: clinicaltrials.gov numbers: NCT04800965 and NCT04801524

Funding Statement: Funding support for this research was provided by UCLA Health, Anderson School of Management, and Carnegie Mellon University.

Declaration of Interests: The authors declare no competing interests.

Ethics Approval Statement: This research was approved by the UCLA Institutional Review Board, which granted a waiver of informed consent.

Note: *The first two authors contributed equally to this work. Trial Registration: clinicaltrials.gov numbers: NCT04800965 and NCT04801524

Funding Statement: Funding support for this research was provided by UCLA Health, Anderson School of Management, and Carnegie Mellon University.

Declaration of Interests: The authors declare no competing interests.

Ethics Approval Statement: This research was approved by the UCLA Institutional Review Board, which granted a waiver of informed consent.

Keywords: vaccination, COVID-19, nudges, RCT, psychological ownership, information intervention

JEL Classification: I12

Suggested Citation

Dai, Hengchen and Saccardo, Silvia and Han, Maria and Roh, Lily and Raja, Naveen and Vangala, Sitaram and Modi, Hardikkumar and Pandya, Shital and Sloyan, Michael and Croymans, Daniel, Behavioral Nudges Increase COVID-19 Vaccinations: Two Randomized Controlled Trials (June 1, 2021). Available at SSRN: https://ssrn.com/abstract=3817832 or http://dx.doi.org/10.2139/ssrn.3817832

Hengchen Dai (Contact Author)

University of California, Los Angeles (UCLA) - Anderson School of Management ( email )

110 Westwood Plaza
Los Angeles, CA 90095-1481
United States

Silvia Saccardo

Carnegie Mellon University, Department of Social and Decision Sciences ( email )

Pittsburgh, PA 15213-3890
United States

Maria Han

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Lily Roh

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Naveen Raja

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Sitaram Vangala

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Hardikkumar Modi

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Shital Pandya

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Michael Sloyan

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

Daniel Croymans

University of California, Los Angeles (UCLA) - UCLA Health System ( email )

10833 Le Conte Avenue
17-165 CHS
Los Angeles, CA 90095-1730
United States

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