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The influence of admission procedures on trust in vaccines
Last registered on March 22, 2021

Pre-Trial

Trial Information
General Information
Title
The influence of admission procedures on trust in vaccines
RCT ID
AEARCTR-0007388
Initial registration date
March 18, 2021
Last updated
March 22, 2021 1:16 PM EDT
Location(s)

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Primary Investigator
Affiliation
ifo Institute - Leibniz Institute for Economic Research at the University of Munich
Other Primary Investigator(s)
PI Affiliation
University of Innsbruck
PI Affiliation
University of Innsbruck
PI Affiliation
UMIT TIrol
Additional Trial Information
Status
In development
Start date
2021-03-26
End date
2022-12-31
Secondary IDs
Abstract
Recent surveys show that about 25 to 42 percent of Germans do not intend to vaccinate against Covid-19. However, ensuring high uptake rates is crucial for achieving herd immunity. One reason why vaccination readiness may be low is due to low trust in the vaccine. In a randomized vignette study, we investigate how the duration and type of the vaccine admission process affects trust in the vaccine, and intentions to get vaccinated.
External Link(s)
Registration Citation
Citation
Angerer, Silvia et al. 2021. "The influence of admission procedures on trust in vaccines ." AEA RCT Registry. March 22. https://doi.org/10.1257/rct.7388-1.0.
Sponsors & Partners

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Experimental Details
Interventions
Intervention(s)
We investigate whether the duration and type of vaccine admission process affects trust in the vaccine, and intentions to get vaccinated. Therefore, we plan to run a vignette experiment in a nationally representative survey in Germany. We present respondents different hypothetical vignetts that describe a new anti-Covid vaccine. Across vignettes, we vary (i) the duration of the admission process, and (ii) the type of admission. After presenting the vignettes, we elicit respondents’ trust in the vaccine, intentions to get vaccinated.
Intervention Start Date
2021-03-26
Intervention End Date
2021-04-30
Primary Outcomes
Primary Outcomes (end points)
Trust in the vaccine (3 outcomes), intention to get vaccinated (1 outcome), and willingness to pay for the vaccine (2 outcomes). In our main analysis, we will create summary indices of these outcomes and estimate treatment effects on these indices. We will also investigate treatment effects on the individual outcomes.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We conduct the experiment in a sample of 2,000 adults aged between 18 and 69 years. The survey is conducted in cooperation with a survey institute. The recruitment and polling is managed by the survey institute, who collects the data via an online platform. That is, our participants answer the survey questions autonomously on their own digital devices. Randomization is carried out by the survey institute at the individual level, using a computer.
Our experiment is structured as follows:
Respondents of the survey will be randomly assigned (between subject) to
Treatment I (p=0.25), Treatment II (p=0.25), Treatment III (p=0.25), or Treatment IV (p=0.25).

Treatment I:
Stage 1: Presentation of vignette (version 1)
Stage 2: Questions: trust in the vaccine + intentions to get the vaccine.
Treatment II:
Stage 1: Presentation of vignette (version 2)
Stage 2: Questions: trust in the vaccine + intentions to get the vaccine.
Treatment III:
Stage 1: Presentation of vignette (version 3)
Stage 2: Questions: trust in the vaccine + intentions to get the vaccine.
Treatment IV:
Stage 1: Presentation of vignette (version 4)
Stage 2: Questions: trust in the vaccine + intentions to get the vaccine.
Experimental Design Details
Not available
Randomization Method
Randomization is carried out by the survey company respondi, using a computer.
Randomization Unit
at the individual level
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
2,000 individuals (adults aged between 18 and 69 years)
Sample size: planned number of observations
2,000 individuals — 500 per treatment
Sample size (or number of clusters) by treatment arms
2,000 individuals — 500 per treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Ethics Committee at the Department of Economics at the Ludwig-Maximilians-University Munich
IRB Approval Date
2021-03-03
IRB Approval Number
2021-06