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Field
Last Published
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Before
October 31, 2019 12:42 AM
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After
December 12, 2019 04:49 PM
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Field
Experimental Design (Public)
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Before
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.
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After
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.
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Field
Randomization Method
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Before
We will use computer randomization via Qualtrics.
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After
We will use computer randomization via Facebook.
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Field
Planned Number of Observations
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Before
Approximately 1,400 men (980 African American men and 420 Caucasian men) will be recruited.
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After
Approximately 5,100 men (3,444 African American men and 1,656 Caucasian men) will be recruited.
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Field
Sample size (or number of clusters) by treatment arms
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Before
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.
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After
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.
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Field
Power calculation: Minimum Detectable Effect Size for Main Outcomes
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Before
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.
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After
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.
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