Back to History Current Version

Self-selective Belief Updating: A Survey Experiment on COVID-19 Vaccine Information

Last registered on October 27, 2021
View Trial History

Pre-Trial

Trial Information

General Information

Title
Self-selective Belief Updating: A Survey Experiment on COVID-19 Vaccine Information
RCT ID
AEARCTR-0008272
Initial registration date
October 26, 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
October 27, 2021, 10:39 PM EDT

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

Locations

Country
Taiwan, Province of China
Region

Primary Investigator

Name
ChienHsun Lin
Affiliation
UCSB
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Hans Hanpu Tung
PI Affiliation
National Taiwan University
Contact Investigator

Additional Trial Information

Status
In development
Start date
2021-11-01
End date
2021-11-15
Keywords
Behavior, Health
Additional Keywords
Media, Information
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We conduct an online survey experiment providing information about vaccines from different manufacturers of COVID-19 to subjects below 20 years old in Taiwan. We provide the subjects information sheets about the vaccines from different manufacturers, which include information such as efficacy, safety, and the platform that the vaccines use. Then we see how the subjects update their beliefs about the vaccines and how their preferences on different vaccines change. In order to identify the effect in belief updating of following two factors (1) the self-selection in consumption of information and (2) the motivated updating from information, we designed 3 treatments: (A) allowing subject to freely choose which and how many information sheet to read, (B) allow subjects to choose a fixed amount of information to read, and (C) assign a fixed amount of information sheets for subjects to read.
External Link(s)

Registration Citation

Citation
Lin, ChienHsun and Hans Hanpu Tung. 2021. "Self-selective Belief Updating: A Survey Experiment on COVID-19 Vaccine Information." AEA RCT Registry. October 27. https://doi.org/10.1257/rct.8272-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2021-11-01
Intervention End Date
2021-11-15

Primary Outcomes

Primary Outcomes (end points)
The change in beliefs on different attributes of vaccines, including: efficacy, hospitalization prevention rates, and adverse event rates.
Primary Outcomes (explanation)
We survey the subjects about their beliefs on the attributes of different vaccines before and after the intervention. In the intervention, or the "information sheets", these attributes are provided. We also defined these terms to eliminate potential misunderstanding.

Secondary Outcomes

Secondary Outcomes (end points)
The change in preferences to different vaccines.
Secondary Outcomes (explanation)
We evaluate the preferences by directly asking the degree of preference and by the willingness to wait for a full vaccine shot.

Experimental Design

Experimental Design
We provide the information about the vaccines collected from WHO and peer-reviewed scientific reports. In the experiment, we provide subjects the information sheets, and they declare their beliefs about the attributes and preferences about vaccines.
Experimental Design Details
In the experiment, we have three main treatment arms.
(1) Free Choice
In this treatment arm, the subjects can freely choice 0-3 out of 5 information sheets about vaccines to read.
(2) Top 3 Choice
In this treatment arm, the subjects can choice the top 3 out of 5 information sheets about vaccines to read.
(3) Assigned
In this treatment arm, the subjects are assigned 3 out of 5 information sheets about vaccines to read.

Before the information, we let all subjects in the above three treatment arms rank the 5 treatment sheets and choose the amount of sheets to read. In order to eliminate possible bias from using the strategic methods, we add 2 more arms as robustness check.
(2*) Top 3 Choice - No Amounts
In this treatment arm, the subjects can choice the top 3 out of 5 information sheets about vaccines to read, while they are not asked of the number of the sheets they want to read.
(3*) Assigned - No Ranking
In this treatment arm, the subjects are assigned 3 out of 5 information sheets about vaccines to read, while they are neither asked of the ranking among sheets nor asked of the amount of sheets they want to read.
Randomization Method
Randomization done by the survey platform (Qualtrics).
Randomization Unit
individual.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1100 individuals.
Sample size: planned number of observations
1100 individuals.
Sample size (or number of clusters) by treatment arms
300 free-choices
300 top 3-choices
300 assigned
100 top 3-choices without asking amounts
100 assigned without asking rankings
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Research Ethics Committee, National Taiwan University
IRB Approval Date
2021-03-15
IRB Approval Number
202102HS016
IRB Name
Human Subjects Committee, Office of Research, University of California, Santa Barbara
IRB Approval Date
2021-09-03
IRB Approval Number
23-21-0388
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.

Request Information

Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials