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Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects
Last registered on January 22, 2020

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
January 22, 2020 4:33 PM EST
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. 2020. "Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects." AEA RCT Registry. January 22. https://doi.org/10.1257/rct.4796-1.4000000000000001.
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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 5,100 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 Facebook.
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 5,100 men (3,444 African American men and 1,656 Caucasian men) will be recruited.
Sample size (or number of clusters) by treatment arms
Approximately 5,100 men will be recruited. Each subject will be randomly assigned to either concordance or discordance group with 50/50 chance. For African American subjects assigned to a concordant actor, the subjects will then be assigned to either a doctor or layperson with a 50% chance. For African American subjects assigned to a discordant actor, all subjects will be assigned to a doctor actor but will be randomly assigned to either a validation message or normal message with a 50% chance. All Caucasian subjects will be assigned to a doctor actor delivering a normal message.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We need a sample size of 5,100 (3,444 black and 1,656 white respondents) to test our main hypotheses with 80% power and at a significance level of 0.05. Using a sample size of 5,100 we can detect a difference in means (in standard deviation units) of (1) 0.08 between concordance and discordance group for both races; (2) 0.12 between concordance and discordance group within black respondents assigned to an authority figure; (3) 0.14 between concordance and discordance group within white respondents assigned to an authority figure; and (4) 0.14 between validation (M2) and normal message (M1) group within black respondents assigned to a discordant authority figure.
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_21Jan2019.pdf

MD5: b6acf2afbc3eca0490e9f61236d6283b

SHA1: dcf274607b24ee4525808455d1f56cf6018c084e

Uploaded At: January 22, 2020