Brief Summary

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.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

3,245

participants targeted

Target at P75+ for not_applicable

Timeline

Completed

Started Dec 2019

Geographic Reach

1 country

1 active site

Status

completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

1.2 years study duration

First Submitted

Initial submission to the registry

November 8, 2019

Completed

5 days until next milestone

First Posted

Study publicly available on registry

November 13, 2019

Completed

1 month until next milestone

Study Start

First participant enrolled

December 20, 2019

Completed

1.2 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 19, 2021

Completed

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 19, 2021

Completed

4 months until next milestone

Results Posted

Study results publicly available

June 29, 2021

Completed

Last Updated

June 29, 2021

Status Verified

June 1, 2021

Enrollment Period

1.2 years

First QC Date

November 8, 2019

Results QC Date

May 28, 2021

Last Update Submit

June 26, 2021

Conditions

Flu, Human Influenza, Human Covid19

Keywords

Belief UpdatingPreventive CareRacial Disparity

Outcome Measures

Primary Outcomes (8)

Rating of Sender
This is an inverse-covariance-weighted index comprised of responses to survey questions regarding: 1. whether the respondent was interested in further medical advice from the given sender (measured as a binary outcome); 2. whether the respondent trusted advice from the sender measured on a scale of 1 to 5; 3. and whether the respondent's assessment of the sender's qualification to provide medical advice measured on a scale of 1 to 5. It is standardized to a mean of 0 and standard deviation of 1. Scores less than 0 indicate lower ratings of the sender rated by participants in Arm A (described in each arm/group description) compared to the rating rated by participants in Arm B (also described in each arm/group description). Scores greater than 0 indicate higher ratings of the sender by Arm A compared to by Arm B. For example, an index score of .18 indicates that participants in Arm A rate the sender 0.18 index (in standard deviation units) higher than those in Arm B.
This outcome was assessed during Baseline survey, which took approximately 20 minutes.
Rating of Signal
This is an inverse-covariance-weighted index comprised of responses to survey questions on: 1. recommending the video to friends and family measured on a scale of 0 to 10; 2. recommending the flu shot to friends and family measured on a scale of 0 to 10; 3. and the respondent's assessment of the extent to which the information contained in the video was useful measured on a scale of 1 to 5. It is standardized to a mean of 0 and standard deviation of 1. An index score of 0 is equal to the mean. Scores less than 0 indicate lower ratings of the signal rated by participants in Arm A (described in each arm/group description) compared to the rating rated by participants in Arm B (also described in each arm/group description). Scores greater than 0 indicate higher ratings of the signal by Arm A compared to by Arm B. For example, an index score of 0.14 indicates that participants in Arm A rate the signal 0.14 index (in standard deviation units) higher than those in Arm B.
This outcome was assessed during Baseline survey, which took approximately 20 minutes.
Signal Content Recall
This is an inverse-covariance-weighted index comprised of responses to survey questions on: 1. whether age group for whom the flu vaccine is recommended (measured as a binary outcome); and 2. whether the flu shot contains the flu virus (recall of information discussed in the video) (measured as a binary outcome). It is standardized to a mean of 0 and standard deviation of 1. An index score of 0 is equal to the mean. Scores less than 0 indicate lower level of recalling signal content among participants in Arm A (described in each arm/group description) compared to the level among participants in Arm B (also described in each arm/group description). Scores greater than 0 indicate a higher level of recalling signal content among participants in Arm A compared to those in Arm B. For example, an index score of 0.02 indicates that participants in Arm A recall signal content 0.02 index (in standard deviation units) higher than those in Arm B.
This outcome will be assessed during Baseline survey, which takes approximately 20 minutes.
Safety Beliefs
This is an inverse-covariance-weighted index comprised of: 1. the point belief on the likelihood to contract the flu from the flu shot measured by a Likert scale and rescaled to have a support of -1 to 1. 2. the certainty measured with a balls and bins method and rescaled to have a support of -1 to 1. It is standardized to a mean of 0 and standard deviation of 1. An index score of 0 is equal to the mean. Scores less than 0 indicate a lower level of beliefs in the safety of flu vaccine among participants in Arm A (described in each arm/group description) compared to the level among participants in Arm B (also described in each arm/group description). Scores greater than 0 indicate a higher level of beliefs among participants in Arm A compared to those in Arm B. For example, an index score of -0.1 indicates that participants in Arm A hold such beliefs 0.1 index (in standard deviation units) lower than those in Arm B.
This outcome will be assessed during Baseline survey, which takes approximately 20 minutes.
Coupon Interest
This is an inverse-covariance-weighted index comprised of revealed preference measures of demand for a free flu shot coupon: 1. Willingness to pay (WTP) for the coupon measured as $0, $1, $2, $5, or $10 2. demand for information regarding locations to redeem the coupon measured as a binary outcome It is standardized to a mean of 0 and standard deviation of 1. An index score of 0 is equal to the mean. Scores less than 0 indicate a lower level of interest in a free flu shot coupon distributed after survey completion among participants in Arm A (described in each arm/group description) compared to the level among participants in Arm B (also described in each arm/group description). Scores greater than 0 indicate a higher level of interest among participants in Arm A compared to those in Arm B. For example, an index score of -0.01 indicates that participants in Arm A hold such interest -0.01 index (in standard deviation units) higher than those in Arm B.
This outcome was assessed during Baseline survey, which took approximately 20 minutes.
(Posterior) Flu Vaccine Intent
This is the respondent's likelihood to receive the flu vaccine before the end of the flu season. This was elicited on an 11-point Likert scale (0 extremely unwilling, 10 extremely willing) after the video message treatment. We re-scaled this outcome to have a scale of 0 to 1. The reported results of the outcome compare participants in Arm A and Arm B (described in each arm/group description). For example, an intent of 0.03 indicates that participants in Arm A are 0.03 units on a scale more likely to intent to take up the flu vaccine compared to those in Arm B.
This outcome was assessed after the video treatment during Baseline survey, which took approximately 20 minutes.
COVID-19 Vaccine Intent
This is the respondent's likelihood to take up the COVID-19 vaccine if made available free of charge. This was elicited on an 11-point Likert scale (0 extremely unwilling, 10 extremely willing) after the video message treatment. We re-scaled this outcome to have a scale of 0 to 1. The reported results of the outcome compare participants in Arm A and Arm B (described in each arm/group description). For example, an intent of 0.04 indicates that participants in Arm A are 0.04 units on a scale more likely to intent to take up the COVID-19 vaccine compared to those in Arm B.
This outcome was assessed after the video treatment during Baseline survey, which took approximately 20 minutes.
Flu Vaccine Take-up
This is respondents' self-report in the follow-up survey on whether they or their family members had received the flu shot or redeemed the coupon since the intervention. The reported results of the outcome compare participants in Arm A and Arm B (described in each arm/group description). For example, 15.0 percentage points indicate that participants in Arm A are more likely to report that they and/or another household member received the flu vaccine by 15.p percentage points compared to those in Arm B.
This outcome was assessed during the follow-up survey which was conducted at least two weeks after the initial baseline survey.

Study Arms (6)

Black R/Race C/Doctor/Standard Script

EXPERIMENTAL

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