We are researchers interested in helping people make decisions. In this task, you will read about hypothetical scenarios about medical drug trials and be asked some related questions. These scenarios range from treatments for high blood pressure to treatments for COVID-19. If you are uncomfortable thinking about these scenarios you may not want to accept the HIT.

If you answer all of the questions, you will earn $2.00. This will take about 10 minutes.



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Blood pressure in high risk patients

Recent studies have shown that lowering systolic blood pressure below 120mm Hg reduces the occurrence of adverse cardiovascular events in high risk patients.

On the next screen we are going to show you information about a hypothetical new medication designed to lower blood pressure in high risk patients and ask you some questions about it.

A hypothetical treatment for hospitalized COVID-19 patients

There are many candidates being explored for treating patients who are hospitalized with COVID-19.

On the next screen we are going to show you information about a hypothetical new treatment for COVID-19 designed to reduce time to recovery for patients hospitalized with COVID-19 and ask you some questions about it.

Results of a hypothetical randomized controlled trial

Suppose that there is a new medication designed to lower blood pressure in high-risk patients, and that it has been tested in a double-blind, randomized controlled trial restricted to patients with high systolic blood pressure.

Each patient's systolic blood pressure was measured by a physician in a pre-treatment examination, and if patients qualified for the trial they were randomly assigned to either a control or treatment group. In the pre-treatment phase, participants in both groups had an average systolic blood pressure of 130mm Hg. There were 150 patients in each of the treatment and control groups.

The control group received a placebo and the treatment group received the new medication. Several months later, each patient's systolic blood pressure was again measured by a physician in a post-treatment examination.

Here is a summary of the results of the trial, which are depicted in the figure to the right:

  • Participants in the control group had an average post-treatment systolic blood pressure of 130mm Hg
  • Participants in the treatment group had an average post-treatment systolic blood pressure of 120mm Hg

Suppose that there is a new medication designed to reduce time to recovery for patients hospitalized with COVID-19, and that it has been tested in a double-blind, randomized controlled trial.

In the trial, patients admitted to the hospital for COVID-19 were randomly assigned to either a control or treatment group. The control group received a placebo and the treatment group received the new medication. The primary outcome was the time to recovery (defined as discharge from the hospital). There were 150 patients in each of the treatment and control groups.

Here is a summary of the results of the trial, which are depicted in the figure to the right:

  • Participants in the control group had an average time to recovery of 13 days
  • Participants in the treatment group had a average time to recovery of 9 days

Outcomes were approximately normally distributed in both groups before and after the treatment, with roughly equal percentages of patients falling above and below the average.

Your estimate

What is your best estimate of the probability that, after the experiment, a randomly selected patient in the treatment group had a lower systolic blood pressure than a randomly selected patient in the control group? (A 50% probability would indicate no difference in outcomes between the treatment and control groups.)
What is your best estimate of the probability that a randomly selected patient in the treatment group recovered more quickly than a randomly selected patient in the control group? (A 50% probability would indicate no difference in outcomes between the treatment and control groups.)
%

Another estimate

Based on its effectiveness and the price of other medications, how much do you think a 30 day supply of this new medication would be worth to patients with high blood pressure? For reference, a 30 day supply of generic ACE inhibitors, also used to lower blood pressure, costs about $20. Based on its effectiveness and the price of other medications, how much do you think a 5 day supply of this new medication would be worth to patients hospitalized with COVID-19? For reference, a 5 day supply of the most popular drug used for this purpose costs about $2500.
$

A question about data from the previous page

What kind of error bars were shown in the plot on the previous page?


A Closer Look

Your expectations for the control condition (the placebo)

If you were to treat 100 patients using the placebo described in the randomized controlled trial you just read about, how many patients do you think would have a post-treatment systolic blood pressure in each range? Recall that the average post-treatment systolic blood pressure with the placebo (the control condition) was 130mm Hg.
If you were to treat 100 patients using the placebo described in the randomized controlled trial you just read about, how many days do you think it would take each patient to recover? Recall that the average time to recovery with the placebo (the control condition) was 13 days.
Please use the +/- buttons to show how many patients you think you would see in each systolic blood pressure range.
Please use the +/- buttons to show how many patients you think would recover in each day range.
You have 100 patients left to place.

Your expectations for the treatment condition (the new medication)

If you were to treat 100 patients using the new medication described in the randomized controlled trial you just read about, how many patients do you think would have a post-treatment systolic blood pressure in each range? Recall that the average post-treatment systolic blood pressure with the new medication (the treatment condition) was 120mm Hg.
If you were to treat 100 patients using the new medication described in the randomized controlled trial you just read about, how many days do you think it would take each patient to recover? Recall that the average time to recovery with the new medication (the treatment condition) was 9 days.
Please use the +/- buttons to show how many patients you think you would see in each systolic blood pressure range.
Please use the +/- buttons to show how many patients you think would recover in each day range.
You have 100 patients left to place.

A second scenario

On the next screen we are going to show you another scenario about a hypothetical new medication designed to lower blood pressure in high risk patients and ask you some questions about it.

On the next screen we are going to show you another scenario about a hypothetical new treatment for COVID-19 designed to reduce time to recovery and ask you some questions about it.

Whereas in the previous scenario the error bars showed two standard errors above and below the average in each group, in the next scenario the error bars show two standard deviations above and below the average in each group.

Thank you!

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