Behavioral Nudges Increase COVID-19 Vaccinations: Two Randomized Controlled Trials
80 Pages Posted: 5 Apr 2021
Date Written: April 1, 2021
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: Suggested Citation