Logical Reasoning

PT106 · S1 · Q25 McKinley: A double-blind study

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McKinley: A double-blind study, in which neither the patient nor the primary researcher knows whether the patient is being given the drug being tested or a placebo, is the most effective procedure for testing the efficacy of a drug.

McKinley's Conclusion

We will not be able to perform a double-blind study on the new drug.

McKinley's Evidence

The drug will have various effects on patients' bodies that will make researchers and patients aware of who got the drug versus the placebo.

Engle's Critique

We could still have a double blind study. You don't know the outcome of the study.

Anticipate

Question stems about the 2nd person "interpreting" the 1st person are basically a subtype of Flaw. They're asking us what's wrong with the 2nd person's interpretation. We read the 1st person's statements charitably and carefully so that we're better able to defend them against the 2nd person's confused rebuttal.

Why does Engle think you would need to know the outcome of the study in order to know whether the drug is having various effects that the placebo doesn't have?

Clinical studies of drugs are designed in order to assess whether the drug achieves a certain effect for the patient. When they're testing Ozempic to see if it achieves weight loss for the patient, they have a placebo group who doesn't get Ozempic (they get a fake sugar pill). To firmly establish that Ozempic is what's causing any weight loss, we want to see that the Ozempic group lost more weight than the control group who got the placebo.

Engle is talking about THOSE kinds of effects. You don't know whether Ozempic helps people lose weight, until the study is over and you look at the data, He's thinking, We already know that one of the chemicals in Ozempic makes people have to pee all the time", so he might be saying "we won't be able to stay 'blind' for long, because we'll know that the frequent-urinators received Ozempic."

Goal

The right answer should describe Engle's read of McKinley: that McKinley meant the desired effect of the drug (e.g. help someone lose weight), not some known side effect (like small bladder syndrome).

25.

Engle's statement indicates that he is most likely interpreting McKinley's remarks to be

  1. Presuming that a double-blind study

    Bad Description

    Engle does not accuse McKinley of treating double-blind studies as the only effective testing method. McKinley described it as "the most effective procedure," not the only one — and Engle's critique is about assuming the outcome, not about ranking procedures.

    3% picked this

  2. Denying that the drug will

    Bad Description

    Engle does not accuse McKinley of denying the drug's effectiveness. Engle is doing the opposite: Engle is saying McKinley is presupposing the drug will have effects (as in, the intended effect of the drug being tested). The confusion is about whether we're talking about the side effects or the intended effect of the drug.

    5% picked this

  3. Presuming that the placebo will

    Bad Description

    Engle says nothing about the placebo. The confusion is about side effects vs. intended effects of the actual drug.

    46% picked this

  4. Correct

    Referring to the drug’s therapeutic

    Why this is right

    "Therapeutic effects" would mean "the effect the drug is intended to have". If a doctor has a male patient high cholesterol, she might prescribe him a medication to lower his cholesterol, which would be the "therapeutic effect" of the drug. The drug might have other incidental effects, like dry mouth, which are side effects. The "outcome of the study" is a measurement of whether the drug was effective at performing the therapeutic use case for which it's intended. McKinley is presumably talking about known side effects of the drug, which we might know before even conducting the study (we might be testing a drug that we already use with dementia and seeing if it has any therapeutic benefit for PTSD).

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

    35% picked this

  5. Based on a confusion about

    Bad Description

    The idea of an efficacious drug would mean one that performs its intended effect. But Engle isn't saying McKinley is confused about how to define when a drug is considered efficacious. Engle is pointing out that we don't know whether a drug is efficacious until the study is over, because he's confused about what type of effects McKinley was talking about (side effects vs. intended effect).

    11% picked this

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