Perceptions of Electoral Credibility in the 2022 Brazilian Presidential Election

Last registered on March 14, 2024


Trial Information

General Information

Perceptions of Electoral Credibility in the 2022 Brazilian Presidential Election
Initial registration date
September 15, 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
September 19, 2022, 4:17 PM EDT

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

Last updated
March 14, 2024, 2:23 PM EDT

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



Primary Investigator

UCLA Political Science Department

Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project addresses two points concerning the spread of misinformation related to the upcoming 2022 Brazilian presidential election: 1) if traditional ways of ensuring electoral credibility are insufficient to persuade skeptics and 2) the extent to which misinformation can be corrected. In a survey experiment, participants are randomly exposed to positive and neutral information about the election or just neutral information. The intervention takes the form of critical thinking about the election and social pressure.

This project seeks to answer:
1) In countries with weak institutional trust, what, if anything, will convince partisan voters that an election was fair?
2) In an environment saturated with false information, is it possible to correct or partially correct these beliefs?
External Link(s)

Registration Citation

Berwald, Rachel. 2024. "Perceptions of Electoral Credibility in the 2022 Brazilian Presidential Election." AEA RCT Registry. March 14.
Experimental Details


Participants will be exposed to positive information about the election through interacting with headlines and mock posts.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
How respondents rate their trust in the election's credibility and why
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This project is a survey experiment with four primary sections:
1) Background information (demographics, social media usage, vote choice in the 2018 presidential election)
2) Measures of institutional trust
3) Experimental or control section (headlines and mock posts)
4) Questions about the 2022 election
Experimental Design Details
The survey will have four primary sections. The first will ask for demographic information, social media usage, and for whom the respondent voted in the 2018 presidential runoff and the extent to which they believed the election to be credible. The second section will ask respondents to rate their trust in various institutions. The third section will be the experimental section which will address the mental model. Here, I will measure my treatment based on the two tenets of information and social pressure as explained above. Those randomly sorted into the treatment group will be exposed to positive headlines about the election’s credibility as well neutral headlines (facts about the election). Those sorted into the control group will only be exposed to neutral headlines. The final section will pertain to the 2022 election where I will ask respondents for whom they intend on voting in October, the extent to which they believe the election will be credible, and why.
Randomization Method
Randomization is done automatically through the survey software which randomly sorts participants into the treatment or control group.
Randomization Unit
Randomization is done on the individual level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
1000 survey completions
Sample size: planned number of observations
1000 survey completions
Sample size (or number of clusters) by treatment arms
Roughly 500 survey completions will be in the treatment group and 500 will be in the control group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
I will need roughly 212 participants who doubt the credibility of the election in order to see an effect.

Institutional Review Boards (IRBs)

IRB Name
Office of the Human Research Protection Program at UCLA
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Intervention Completion Date
September 29, 2022, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
September 29, 2022, 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
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials