Vaccination as personal public-good provision

Last registered on August 11, 2024
View Trial History

Pre-Trial

Trial Information

General Information

Title
Vaccination as personal public-good provision
RCT ID
AEARCTR-0008216
Initial registration date
September 10, 2021

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
September 12, 2021, 11:18 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
August 11, 2024, 5:30 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country
United States of America
Region

Primary Investigator

Name
Lucas Reddinger
Affiliation
UCSB
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Gary Charness
PI Affiliation
UCSB
Contact Investigator
PI Name
David Levine
PI Affiliation
UC Berkeley Haas
Contact Investigator

Additional Trial Information

Status
Completed
Start date
2021-04-07
End date
2021-10-13
Keywords
Behavior, Health, Lab
Additional Keywords
pro-social behavior, vaccination, behavioral public health, COVID-19, public-good game, experimental economics
JEL code(s)
I12, D91, C90
Secondary IDs
NIH 2P30AG012839
Prior work
This trial is based on or builds upon one or more prior RCTs.
Abstract
Vaccination against infectious diseases has both private and public
benefits. We study whether social preferences---concerns for the
well-being of other people---are associated with one's decision
regarding vaccination. We measure these social preferences for 549
online subjects with a public-good game and an altruism game. To the
extent that one gets vaccinated out of concern for the health of others,
contribution in the public-good game is analogous to an individual's
decision to obtain vaccination, while our altruism game provides a
different measure of altruism, equity, and efficiency concerns. We proxy
vaccine demand with how quickly a representative individual voluntarily
took the initial vaccination for COVID-19 (after the vaccine was widely
available). We collect COVID-19 vaccination history separately from the
games to avoid experimenter-demand effects. We find a strong result:
Contribution in the public-good game is associated with greater demand
to voluntarily receive a first dose, and thus also to vaccinate earlier.
Compared to a subject who contributes nothing, one who contributes the
maximum ($4) is 58% more likely to obtain a first dose voluntarily in
the four-month period that we study (April through August 2021). In
short, people who are more pro-social are more likely to take a
voluntary COVID-19 vaccination. Behavior in our altruism game does not
predict vaccination. We recommend further research on the use of
pro-social preferences to help motivate individuals to vaccinate for
other transmissible diseases, such as the flu and HPV.
External Link(s)

Registration Citation

Citation
Reddinger, Lucas, Gary Charness and David Levine. 2024. "Vaccination as personal public-good provision." AEA RCT Registry. August 11. https://doi.org/10.1257/rct.8216-2.0
Sponsors & Partners

Sponsors

Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2021-09-11
Intervention End Date
2021-10-13

Primary Outcomes

Primary Outcomes (end points)
Prosocial behavior in economic games / whether (and when) individuals report having taken a COVID-19 vaccine dose.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We registered our study “Can targeted messages reduce COVID-19 vaccination hesitancy?” as AEARCTR-0007478 and conducted the trial in April 2021. In August 2021 we followed a sample of these respondents to collect additional participant characteristics.

We sought to attain a follow-up sample balanced between those reporting that they had taken a COVID-19 vaccine dose and those reporting that they had not. To this end, we randomly sampled half of participants who in April said that they intended to take a vaccine dose as soon as possible; we randomly sampled half of participants who were not classified as being a member of any segment of interest; we sampled the entirety of all other subjects. This provided a sample of 2441 participants from the 3668 qualified participants in April.

Of the multitude of characteristics we solicited from participants in August, we have only analyzed one. We tabulated whether (and when) respondents reported having taken a vaccine dose. Our results:

Have you taken a COVID-19 vaccine dose?
No 336 (56%)
Yes, in... 262 (44%)
April 86 (14%)
May 77 (13%)
June 41 (7%)
July 35 (6%)
August 18 (3%)
Unsure 4 (1%)
Prefer not to say 4 (1%)

We have thus achieved a sample well-balanced on our primary characteristic of interest.

We now will follow these participants yet again in an incentivized online session titled “Survey with decision-making for bonus payment.” This session will be run under a different survey account than previous sessions to eliminate any possible framing effects. Each participant is given $4 to play a variety of games that relate to pro-social preferences. We include two games to check participant comprehension. Our regression analyses will include the covariates collected in August. We will test whether pro-social behavior in our incentivized games predicts self-reported vaccination.
Experimental Design Details
Randomization Method
Randomization done in office by a computer. Only sampling is randomized, as we have no intervention.
Randomization Unit
Individual. Only sampling is randomized, as we have no intervention.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
600 individuals.
Sample size: planned number of observations
600 individuals.
Sample size (or number of clusters) by treatment arms
Our study is only observational, but uses unique sampling methods as explained in the experimental design.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
UCSB Human Subjects Committee
IRB Approval Date
2020-10-01
IRB Approval Number
60-20-0658
Analysis Plan

Post-Trial

Post Trial Information

Study Withdrawal

There is information in this trial unavailable to the public. Use the button below to request access.

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Intervention

Is the intervention completed?
Yes
Intervention Completion Date
October 13, 2021, 12:00 +00:00
Data Collection Complete
Yes
Data Collection Completion Date
October 13, 2021, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
549 subjects completed all sessions.
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication

Data Publication

Is public data available?
Yes
Public Data URL
https://doi.org/10.17605/OSF.IO/K6WE2

Program Files

Program Files
Yes
Program Files URL
https://doi.org/10.17605/OSF.IO/K6WE2
Reports, Papers & Other Materials

Relevant Paper(s)

Abstract
Vaccination against infectious diseases has both private and public
benefits. We study whether social preferences---concerns for the
well-being of other people---are associated with one's decision
regarding vaccination. We measure these social preferences for 549
online subjects with a public-good game and an altruism game. To the
extent that one gets vaccinated out of concern for the health of others,
contribution in the public-good game is analogous to an individual's
decision to obtain vaccination, while our altruism game provides a
different measure of altruism, equity, and efficiency concerns. We proxy
vaccine demand with how quickly a representative individual voluntarily
took the initial vaccination for COVID-19 (after the vaccine was widely
available). We collect COVID-19 vaccination history separately from the
games to avoid experimenter-demand effects. We find a strong result:
Contribution in the public-good game is associated with greater demand
to voluntarily receive a first dose, and thus also to vaccinate earlier.
Compared to a subject who contributes nothing, one who contributes the
maximum ($4) is 58% more likely to obtain a first dose voluntarily in
the four-month period that we study (April through August 2021). In
short, people who are more pro-social are more likely to take a
voluntary COVID-19 vaccination. Behavior in our altruism game does not
predict vaccination. We recommend further research on the use of
pro-social preferences to help motivate individuals to vaccinate for
other transmissible diseases, such as the flu and HPV.
Citation
Reddinger, J. L., Gary Charness, and David Levine. 2024. "Vaccination as personal public-good provision." Journal of Economic Behavior & Organization 224 (August) 481--499.
URL
https://doi.org/10.1016/j.jebo.2024.06.015

Reports & Other Materials