Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects

President and Fellows of Harvard College

Status: Completed

Conditions: Influenza, Human; Covid19; Flu, Human

Treatments: Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT04160975

IRB19-1424

Details and patient eligibility

About

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. The investigators plan to recruit male subjects and randomly assign them to four persuasion treatments: three of which vary dimensions of the sender of a medical recommendation (racial concordance and authority treatments) and one which varies the signal (standard vs. empathetic). Specifically, the investigators will show subjects videos of either Black or white actors/actresses providing scripted information on the flu vaccination. The investigators will randomize the race of the sender and if the subject is Black, also randomize the authority of the sender, with the actor portraying either a doctor or a layperson. In addition, the investigators will vary the script used in the experiment between one that acknowledges past injustices (indicated as an empathetic script hereafter) and one that does not (indicated as a standard script hereafter). The investigators will provide subjects a free flu shot coupon and elicit the price at which subjects would be willing to give up this coupon for a cash reward. Lastly, in light of the relevance of vaccination take-up in combating COVID-19 pandemic, the investigators will assess demand for information about a COVID-19 vaccine, with subjects invited to receive results of a safety and efficacy review from a trusted or standard source. The design requires the collection of baseline and endline surveys combined with administrative data from pharmacies about coupon redemption. The primary outcomes of interest are posterior beliefs about seasonal flu vaccination, demand and willingness-to-pay (WTP) for a free flu shot coupon, redemption of the coupon, and demand for information about a COVID-19 vaccine.

Full description

The investigators will recruit approximately 3350 African-American or Caucasian adult males with a high-school diploma or less. A pilot study, which ran during the 2019-20 flu season, recruited approximately 850 subjects, and a planned scale-up will recruit an additional 2500 subjects during the 2020-21 flu season. The investigators 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. The investigators 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, the investigators will obtain information on beliefs regarding vaccination, feedback on the video, attention to the video and willingness-to-pay for a flu shot coupon. The final baseline module will consist of a randomly assigned invitation to receive the results of an upcoming review of a COVID-19 vaccine, with subjects assigned to receive information from a trusted or standard source. The investigators will track flu coupon redemption, which is redeemable at most pharmacies nationwide.

Enrollment: 3,245 patients

Sex: Male

Ages: 18 to 51 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Age: See above.
• Education: Less than a college degree.
• Gender: Male.
• Race: Caucasian or African American.
• Miscellaneous: Has not received the flu shot in the current flu season yet.
• Miscellaneous: Has sound on his device turned on.

Exclusion criteria

• Fast survey-taking: subjects who are among the 5% fastest in terms of total time spent on survey within race and treatment group.
• Nonsense answers (those that do not have decipherable English) in the open text sections that suggest low effort.
• Inconsistent responses to questions (such as being willing to give up $10 to receive a flu coupon but not $1).
• Repeat survey takers as indicated by duplicate emails or IP addresses in survey data.

Trial design

Primary purpose: Health Services Research

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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3,245 participants in 6 patient groups

Black R/Race C/Doctor/Standard Script

Experimental group

Description:

Video which contains a racially concordant actor playing a doctor and reading a standard script. The receiver of the message will be Black.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

Black R/Race C/Layperson/Standard Script

Experimental group

Description:

Video which contains a racially concordant actor playing a layperson and reading a standard script. The receiver of the message will be Black.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

Black R/Race D/Doctor/Standard Script

Experimental group

Description:

Video which contains a racially discordant actor playing a doctor and reading a standard script. The receiver of the message will be Black.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

Black R/Race D/Doctor/Acknowledgement Script

Experimental group

Description:

Video which contains a racially discordant actor playing a doctor and reading an acknowledgement script. The receiver of the message will be Black.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

White R/Race C/Doctor/Standard Script

Experimental group

Description:

Video which contains a racially concordant actor playing a doctor and reading a standard script. The receiver of the message will be White.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination

White R/Race D/Doctor/Standard Script

Experimental group

Description:

Video which contains a racially discordant actor playing a doctor and reading a standard script. The receiver of the message will be White.

Treatment:

Behavioral: Video about safety and effectiveness of adult seasonal flu vaccination