#62614 | AsPredicted

'Efficacy of requirements on vaccination'
(AsPredicted #62614)

Created:       04/05/2021 03:08 AM (PT)

This is an anonymized version of the pre-registration.  It was created by the author(s) to use during peer-review.
A non-anonymized version (containing author names) should be made available by the authors when the work it supports is made public.

1) Have any data been collected for this study already?
No, no data have been collected for this study yet.

2) What's the main question being asked or hypothesis being tested in this study?
We will test the efficacy of vaccination requirements. We predict that vaccination intention against an infectious disease would be greater when participants are informed that getting the vaccine is required versus not.

3) Describe the key dependent variable(s) specifying how they will be measured.
Intention to vaccinate against an infectious disease

4) How many and which conditions will participants be assigned to?
We will employ two experimental conditions. Specifically, participants will be asked to consider a situation in which their job either requires them to get vaccinated against a new disease (requirement condition) or their job simply informs them that they themselves have to make the decision of whether to vaccinate against a new disease (no requirement condition).

5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
We will conduct ANOVA tests to compare the vaccination intention across the two experimental conditions.

6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
Pretests demonstrate that this study takes at least five minutes to complete. We will exclude participants who completed the survey in less than one minute, which could signal their inattention to the survey materials.

7) How many observations will be collected or what will determine sample size?
No need to justify decision, but be precise about exactly how the number will be determined.

We will terminate the data collection when the sample size reaches 600.

8) Anything else you would like to pre-register?
(e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?)

We will include a battery of questions for exploratory purposes. The items will include perceived norms for vaccination, perceived benefits of vaccination, perceived fairness of vaccination, perceived risk of the disease and the vaccine, perceived obligation to vaccinate, and perceived freedom of vaccination. We will explore whether these constructs mediate the effect of requirements on intentions to receive the vaccine.
In addition, we will include several individual differences measures, including the need to belong, anxiety, vaccine hesitancy, reactance, moral values, political ideology, conservative/liberal media use to explore whether our proposed effects are moderated by these individual differences.