Back to History

Fields Changed

Registration

Field Before After
Trial Title Persuasion in Health Persuasion in Medicine: Experimental Evidence on Sender and Signal Effects
Abstract Prior research has found that patient-doctor racial concordance is important for increasing the demand for preventive healthcare among low-income African American men, particularly for invasive services. Although results were consistent with better communication as the mechanism, other explanations, such as differential messaging or doctor quality, were difficult to exclude. To eliminate confounding from these factors and uncover which aspects of communication are particularly important for influencing health behaviors, we propose a pilot RCT randomizing black and white adult male subjects to infomercials featuring black and white male physician-actors. The content of the infomercial is the safety and effectiveness of adult seasonal flu vaccination. We hold the signal (i.e. the infomercial script) constant, while varying features of the sender (i.e. race and authority). By including black and white respondents, we test whether concordance effects differ across race. 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 voucher, level of attention and recall from the infomercial video, and redemption of said voucher. 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.
Last Published October 16, 2019 07:36 PM October 31, 2019 12:42 AM
Intervention (Public) The study subjects will be randomly assigned to one of several informational videos. Each video will contain one of black or white male actors playing the role of either a doctor or a layperson. The actors will be provided with a script of information to read. The script will be about the safety and effectiveness of adult seasonal flu vaccination. We will hold the signal (i.e. the infomercial script) constant, while varying features of the sender (i.e. race and authority). Through this intervention, we will test whether concordance effects differ across race and/or authority. 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 October 15, 2019 October 31, 2019
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 voucher, level of attention and recall from the infomercial video, and redemption of said voucher. 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.
Experimental Design (Public) We will recruit approximately 1,400 African American or Caucasian male subjects aged 25-50 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 infomercials which contain one of black or white actors playing the role of either a doctor or a layperson. The content of the infomercial will be the safety and effectiveness of adult seasonal flu vaccination. After the video, we will ask subjects whether they would like to receive a free flu shot coupon. we will ask about their beliefs regarding flu vaccination and the video, and the willingness-to-pay for a flu shot coupon. We will track coupon redemption, which is redeemable at most pharmacies nationwide. 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.
Randomization Method We are using computer randomization via Qualtrics. We will use computer randomization via Qualtrics.
Planned Number of Clusters Not applicable Not applicable - though we may need to correct for correlation in the error term across actor-script-types.
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. 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.
Power calculation: Minimum Detectable Effect Size for Main Outcomes This is a pilot study, where the sample size is determined by the budget and allows us to work on the feasibility and logistics of the intervention. 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.
Public analysis plan No Yes
Back to top

Analysis Plans

Field Before After
Document
pre_analysis_plan_30oct2019.pdf
MD5: a5faf6f75775f9ae67976e87a4ecdcd5
SHA1: 32d860d786d36477aa849d7e4819c943b9e71b39
Title Pre-analysis plan for Persuasion in Medicine
Back to top