LR Question 25 Explanation
QUESTION TEXT: McKinley: A double blind study, in which neither the…
QUESTION TYPE: Misinterpretation
ARGUMENTS: McKinley concludes we can’t use a double blind study, because the drug will have obvious effects.
Engle thinks that McKinley is being hasty, since he doesn’t know what the drug will do.
ANALYSIS: Drugs can have multiple effects. They (hopefully) heal us, but they often also produce side-effects.
You might know if a drug has certain visible side effects, even if you’re not yet sure whether the drug works. Maybe this new drug temporarily turns patients purple.
Engle is assuming that McKinley is referring only to the beneficial effect the drug might have. Or all of the drug’s effects.
But it’s quite possible that McKinley knows some of the drug’s effects, even if he doesn’t know all of them.
___________
- If Engle thought this, he would have argued that there was another effective way to study the drug. But Engle doesn’t say that. Instead he argues that the double-blind method could work.
- Engle said McKinley assumed McKinley knew the outcome of the study. But Engle didn’t say which way McKinley thought the study would go.
- McKinley didn’t mention the placebo having effects, and neither did Engle. It would be strange if a placebo had effects. They’re supposed to produce no physical change.
- CORRECT. Engle thought McKinley was saying that he knew the drug would work. He doesn’t realize McKinley might have meant the drug has some obvious side effects, even if the full results are unknown.
- Engle said nothing like this. An example of this would be: Someone thinks a drug works, just because a patient took it and felt better. (We need more information. It could have been some other cause that made the patient better.)
Still trying to wrap my head around this and convince myself why C is incorrect. Is my understanding of double-blind incorrect?
A placebo _can_ produce measurable, physiological changes even in a double-blind study that mimic anticipated results of treatment. Unexpected/Unknown side-effects can also occur in both groups. A quick Google search will pull up plenty of confirmation + studies on this.
Whether it’s a result of conditioned/primed response, expectations that alter the release of chemicals — if a participant attempts to guess whether or not they received the placebo, which often happens, this is totally plausible. While double-blind studies seek to minimize the placebo effect, it can still very much occur?
Is the answer compatible with these facts?
It sounds like you’re interpreting the question as asking “Is C true?” not “Is C what Engle did?”.
Certainly placebo’s can produce impacts. But the issue at question here is maybe it is a cancer treatment drug, which is known to produce a harmless rash. You can’t run a double blind trial with such a drug unless you also have a placebo which produces the same rash.
It is easy to judge a universal side effect of the drug, whereas you can only know if the drug works via a clinical trial. Engle mistakenly assumes the drug will produce a rash only if it works, or something like that. If the drug didn’t work, then we could test it.
This has nothing to do with whether placebos have some kind of effect. The key question for both McKinley and Engle is whether both the test group and control group will see the same kind of side effect which would alert the participants whether they had the drug or a placebo.
No placebo I know of predictably produces specific side effects that would mimic a drug with such side effects. Hope that helps!