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Completed Not applicable Interventional Accepts healthy volunteers Results available

Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects

ClinicalTrials.gov ID: NCT04160975

Public ClinicalTrials.gov record NCT04160975. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 1, 2026, 5:19 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

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.

Study identification

NCT ID
NCT04160975
Recruitment status
Completed
Study type
Interventional
Phase
Not applicable
Lead sponsor
Harvard University
Other
Enrollment
3,245 participants

Conditions and interventions

Eligibility (public fields only)

Age range
18 Years to 51 Years
Sex
Male
Healthy volunteers
Accepts healthy volunteers

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Dec 19, 2019
Primary completion
Feb 18, 2021
Completion
Feb 18, 2021
Last update posted
Jun 28, 2021

2019 – 2021

United States locations

U.S. sites
1
U.S. states
1
U.S. cities
1
Facility City State ZIP Site status
Harvard University Cambridge Massachusetts 02138

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT04160975, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Jun 28, 2021 · Synced Sep 1, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT04160975 live on ClinicalTrials.gov.

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