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Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects
Last registered on October 31, 2019

Pre-Trial

Trial Information
General Information
Title
Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects
RCT ID
AEARCTR-0004796
Initial registration date
October 15, 2019
Last updated
October 31, 2019 12:42 AM EDT
Location(s)

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Primary Investigator
Affiliation
Harvard Kennedy School
Other Primary Investigator(s)
PI Affiliation
Stanford University
Additional Trial Information
Status
In development
Start date
2019-10-15
End date
2020-06-15
Secondary IDs
Abstract
The aim of the study is to identify what sender/signal combinations are most persuasive in encouraging low socioeconomic males living in the U.S. to take-up seasonal flu vaccination. We plan to recruit male subjects and randomly assign them to three persuasion treatments: two of which vary dimensions of the sender of medical recommendation (concordance and authority treatments) and one which varies the signal (validation). Specifically, we will show subjects videos of either black or white male "actors" providing scripted information on the flu vaccination. We will cross-randomize race with authority as the actor will portray either a actor or a layperson. In addition, we will vary the script used in the experiment between one that acknowledges past injustices and one that does not. Lastly, we will randomize offer prices for a free flu shot coupon. The design requires collection of baseline and endline surveys combined with administrative data from pharmacies about coupon redemption. The outcomes of interest are posterior beliefs about seasonal flu vaccination, demand and WTP for a free flu shot coupon and redemption of the coupon.
External Link(s)
Registration Citation
Citation
Alsan, Marcella and Sarah Eichmeyer. 2019. "Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects." AEA RCT Registry. October 31. https://doi.org/10.1257/rct.4796-1.2.
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Experimental Details
Interventions
Intervention(s)
The aim of our study is to identify what sender/signal combinations are most persuasive in encouraging low socioeconomic males living in the U.S. to take-up seasonal flu vaccination. We plan to recruit male subjects and randomly assign them to three persuasion treatments: two of which vary dimensions of the sender of medical recommendation (concordance and authority treatments) and one which varies the signal (validation). Specifically, we will show subjects videos of either black or white male "actors" providing scripted information on the flu vaccination. We will cross-randomize race with authority as the actor will portray either an actor or a layperson. In addition, we will vary the script used in the experiment between one that acknowledges past injustices and one that does not. Lastly, we will randomize offer prices for a free flu shot coupon. The design requires collection of baseline and endline surveys combined with administrative data from pharmacies about coupon redemption. The outcomes of interest are posterior beliefs about seasonal flu vaccination, demand and WTP for a free flu shot coupon and redemption of the coupon.
Intervention Start Date
2019-10-31
Intervention End Date
2020-02-29
Primary Outcomes
Primary Outcomes (end points)
Our primary outcomes of interest are prior/posterior beliefs about the risk/benefits of the flu shot, perceptions of the sender, willingness-to-pay (WTP) for a free flu shot coupon, level of attention and recall from the infomercial video, and redemption of said coupon.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We will recruit approximately 1,400 African American or Caucasian adult males with a high-school diploma or less. We will oversample African American individuals, emphasizing low-income and minority men because these characteristics are correlated with lower relative take-up of flu vaccination. After informed consent is obtained, subjects will be asked about sociodemographic information (age, education, income and marital status), healthcare experience and past medical history, knowledge and beliefs about flu vaccination, and location of the nearest pharmacy. We will then randomly assign the adult male subjects to videos which contain one of black or white actors playing the role of either a doctor or a layperson as well as different scripts. The content of the infomercial will be the safety and effectiveness of adult seasonal flu vaccination. After the video, we will obtain information on beliefs regarding flu vaccination, feedback on the video, attention to the video and willingness-to-pay for a flu shot coupon. We will track coupon redemption, which is redeemable at most pharmacies nationwide.
Experimental Design Details
Not available
Randomization Method
We will use computer randomization via Qualtrics.
Randomization Unit
The unit of randomization is the individual.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
Not applicable - though we may need to correct for correlation in the error term across actor-script-types.
Sample size: planned number of observations
Approximately 1,400 men (980 African American men and 420 Caucasian men) will be recruited.
Sample size (or number of clusters) by treatment arms
Approximately 1,400 men will be recruited and randomly assigned with a 70% chance of being assigned to an infomercial featuring a physician-actor and a 30% chance of being assigned to an infomercial featuring a layperson-actor. Within each group, subjects will be randomly assigned to either a Caucasian or African American actor with a 50% chance. Within each authority group and sender race, subjects will be randomly assigned with a 50% chance to each script.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
For a sample of approximately 1000 men, we are powered to detect a concordance MDE of 0.17 for the pooled sample and 0.21 within the African-American sample with 80% power and at a significance level of 0.05. For a sample size of 1400, these effect sizes are 0.15 and 0.18, respectively.
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Harvard University
IRB Approval Date
2019-10-11
IRB Approval Number
IRB19-1424
Analysis Plan
Analysis Plan Documents
Pre-analysis plan for Persuasion in Medicine

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Uploaded At: October 31, 2019