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

80 Pages Posted: 5 Apr 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

Daniel Croymans

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

Date Written: April 1, 2021

Abstract

Fighting the COVID-19 pandemic requires quick and effective strategies to maximize vaccine uptake. We present two sequential randomized controlled trials (RCTs) that tackle this challenge with behavioral science insights. We deliver text-based nudges to UCLA Health patients one day (first RCT; N=113,229) and eight days (second RCT; N=90,662) after they receive notifications of vaccine eligibility. In the first RCT, text messages designed to make vaccination salient and easy to schedule boost appointment and vaccination rates by 86% and 26%, respectively. Nudges that make patients feel endowed with the vaccine heighten these effects, but addressing vaccine hesitancy via a video-based information intervention does not yield benefits beyond simple text. These results hold across ethnicity and age groups. By contrast, online experiments (N=2,003) soliciting hypothetical responses to the same messages reveal the opposite patterns, underscoring the importance of pilot-testing behavioral nudges in the real world before scaling them up. In the second RCT, we further find that receiving a second reminder boosts appointment and vaccination rates by 52% and 16%, respectively. Our findings suggest that text-based nudges can substantially increase and accelerate COVID-19 vaccinations at almost zero marginal cost, highlighting the promising role of behavioral science in addressing a critical component of the COVID-19 pandemic response.

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 Croymans, Daniel, Behavioral Nudges Increase COVID-19 Vaccinations: Two Randomized Controlled Trials (April 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

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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