THE IMPACT OF INCENTIVES FOR VACCINATION: INFORMATION PROVISION US

Last registered on June 26, 2022

Pre-Trial

Trial Information

General Information

Title
THE IMPACT OF INCENTIVES FOR VACCINATION: INFORMATION PROVISION US
RCT ID
AEARCTR-0009607
Initial registration date
June 22, 2022

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
June 26, 2022, 5:24 AM EDT

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

Locations

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Primary Investigator

Affiliation
University of Zurich

Other Primary Investigator(s)

PI Affiliation
University of Lausanne
PI Affiliation
University of Copenhagen
PI Affiliation
Columbia University
PI Affiliation
University of Chicago
PI Affiliation
Lund University

Additional Trial Information

Status
In development
Start date
2022-06-22
End date
2023-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We study the impacts of offering monetary incentives for vaccination on future vaccination uptake, safety perceptions, and morals. We use a standard information provision experiment to create random exposure to incentives. We will exploit the fact that many people in the US are unaware that state governments paid people to get vaccinated. The idea is that informing people in the treatment condition that the government paid people to get vaccinated creates random variation in perceived exposure to incentives, allowing us to study the consequences of being exposed to incentives.
External Link(s)

Registration Citation

Citation
Campos-Mercade, Pol et al. 2022. "THE IMPACT OF INCENTIVES FOR VACCINATION: INFORMATION PROVISION US." AEA RCT Registry. June 26. https://doi.org/10.1257/rct.9607
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2022-06-22
Intervention End Date
2022-07-31

Primary Outcomes

Primary Outcomes (end points)
Suppose that there would be a new outbreak of the COVID-19 pandemic in 6 months and the Center for Disease Control would recommend people to take an additional COVID-19 vaccine shot (regardless of the number of shots they got in the past). Thinking of such a situation, would you take an additional shot? (Yes = 1 / No = 0)
Primary Outcomes (explanation)
In our primary analysis we will study whether the treatment (exposure to information about the monetary incentives) effects our primary outcome measure using OLS.

Secondary Outcomes

Secondary Outcomes (end points)
i) Perceived safety and efficacy: Average answer to the following 3 items (Scales: 5-point Likert scale):
- In general, COVID-19 vaccines are safe
- I am worried about the side effects from COVID-19 vaccines (reverse coded)
- In general, COVID-19 vaccines are highly effective at protecting my health

ii) Moral values and norms: Average answer to the following 3 items (Scales: 5-point Likert scale):
- I would be willing to take the personal costs of getting an additional COVID-19 vaccine (e.g., time, discomfort, mild side effects) for the greater good of society
- I think people would have a civic duty or a moral obligation to get an additional COVID-19 vaccine
- Not taking the COVID-19 vaccine would be generally viewed as socially inappropriate in this situation
Secondary Outcomes (explanation)
In our secondary analysis we will study whether the treatment (exposure to information about the monetary incentives) effects our secondary outcome measure using OLS.

We will then also study whether there are heterogeneities in treatment effects. Our main focus lies on vaccination attitudes, income, political ideology, and education.

Experimental Design

Experimental Design
We will randomly inform some participants that the government in their state paid people to get a COVID-19 vaccine. After this information provision intervention, we will elicit participants’ intentions to get a future dose of a COVID-19 vaccine, morals in the context of COVID-19 vaccination, and perceived vaccine safety. To avoid experimenter demand effects, we will follow the standard procedure in information provision experiments: We elicit these outcome measures in a separate survey that we implement a few days after the information provision survey. We will obfuscate the relationship between both surveys, as is common best practice.
Experimental Design Details
Not available
Randomization Method
Randomization is done by a computer
Randomization Unit
Randomization is done at the individual level
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
3000 individuals
Sample size: planned number of observations
3000 individuals
Sample size (or number of clusters) by treatment arms
1500 individuals in each of the two treatment arms
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Considering that around 50% of the participants do not know about the state incentive programs (as we have recently piloted), we have 80% power to detect smaller effect sizes than the benchmark of 0.2 standard deviations for our outcome variables.
IRB

Institutional Review Boards (IRBs)

IRB Name
Human Subjects Committee of the Faculty of Economics, Business Administration, and Information Technology at University of Zurich
IRB Approval Date
2022-06-08
IRB Approval Number
2022-045