Q25 - McKinley: A double-blind study

[rzaman]

Can someone explain question 25?

[bbirdwell]

Please check out how I changed the title of your post and follow that format for future posts

Now, I think this is a tough question! -- mostly because the correct answer seems to contain a concept that is not mentioned in the original argument. In order to get this one right, we really have to play the "which one is most likely" game well.

So what does McKinley say?
1. Double-blind study is most effective way to test efficacy (effectiveness)
2. This new drug will have various effects on patients' bodies.
3. B/c of these effects, we'll be aware of who is who
C: Therefore, we cannot do a double-blind study on this drug

And Engle?
1. You are assuming you know what the outcome will be.
C: Therefore, cannot yet conclude that we cannot do the double-blind study on this drug.

(A) "only" way? Nope.
(B) not even close.
(C) tempting! But no. Perhaps he assumes that the placebo won't have the same effects as the drug, but not necessarily that the placebo will have no effects whatsoever.
(E) not even close.

Now take a look at (D). At first, the word "therapeutic" might have thrown us off. But when Engle says "you are assuming you know what the outcome will be," is that really what McKinley is doing? Well, only if the "effects on the body" that McKinley talks about are the effects the drug is intended to have -- the therapeutic effects.

It might be easier to think about it this way -- what if McKinley was talking about side effects? Would Engle be right to accuse him of assuming to know the outcome? No! The "outcome" is about whether the drug works -- not whether it produces "various effects!"

In other words, McKinley says that we'll be able to tell who is getting which drug, and Engle takes that to mean that we know the drug works (ie we know the outcome).

[rzaman]

Thanks for the help! So if McKinley had been talking about known side effects, then Engle would not have been able to accuse him of assuming he knew the outcome of the study because McKinley could have concluded the results from known side-effects...Is that line of reasoning correct?

[bbirdwell]

You're right, but I think your reasoning is a little off. If McKinley had been talking about known side effects, Engle could not have accused him of assuming the result of the study... because side effects have nothing to do with the result of the study (whether the drug works).

[b16]

"If McKinley had been talking about known side effects, Engle could not have accused him of assuming the result of the study... because side effects have nothing to do with the result of the study (whether the drug works)."

I think this interpretation is backwards. The "known side effects" are actually the key to the question. McKinley is saying that they cannot conduct a double-blind study because "the drug will have various effects on the patients' bodies." Therapeutic effects or known side effects would both be "various effects" that would reveal to the experimenters which patients have the drugs rather than the placebos.

Engle is misinterpreting the "various effects" to mean the "therapeutic effects" rather than the known side effects. If Engle had understood "various effects" to include the known side effects, then Engle would not be challenging McKinley's conclusion since a double-blind study would obviously be ruined once the experimenters notice the known side effects on the patients' bodies.

[redcobra21]

Hey guys,

Sorry, I'm still having some confusion with this problem.

Even if Engle had assumed that McKinley was referring to side effects, I still don't see how his conclusion would be affected. Isn't McKinley just saying that we can't foreclose the option of a double blind study because we don't know if various effects - regardless of whether they are therapeutic or side effects - will actually manifest themselves during the course of the study?

I don't think outcome as it is stated in the conclusion is just about "whether the drug works." When pharma companies talk about "outcome," they generally consider not only whether the drug will work, but also whether there will be any side effects in the first place.

Am I missing something here? Thanks!

[tommywallach]

Hey Red Cobra,

B16 explained this perfectly. If the effects are global (both therapeutic and side), then McKinley's point is good, and Engle couldn't challenge it. He's mistakenly assuming that McKinley is only talking about therapeutic effects, so he has a way to challenge (you're forgetting about side effects).

Make sense?

-t

[nicolauria]

Thanks for all the posts.

Struggled with this one a lot, eventually broke it down into:

McKinley: 1) Double-blind studies using placebo and real drug are most effective for testing the efficacy of a drug.
2) Because this drug will have various effects, study is useless. AKA - We will already know which people are taking the drug and which are taking the placebo.

Engle says hold on a minute, even if we know who is taking the drug and who isn't, that doesn't tell us whether it is effective or not.

(D) - Acknowledges that Engle argues the study is still worth conducting to determine whether the drug is effective or not (therapeutic purposes).

If Engle interpreted McKinley's argument to be focused on side effects, then there would be no point in conducting the study since we can already discern the placebo from the real drug because of the 'various effects'.

Sigh, that was way to drawn out, made better sense in my head. Hope that helped someone.

[deedubbew]

How do we know that "outcome" doesn't refer to side effects?

[tommywallach]

Because the point of a drug is to deal with the underlying condition. Side effects are not related to the outcome of the study.

-t

[deedubbew]

Can't it refer to the overall outcome including both the intended effects and the potential side effects?

[tommywallach]

Hey Deedub,

I thought I just answered that! : )

The outcome, as described here, would be whether or not the drug works to cure the underlying condition. Remember, the point of a drug test is to see if the drug is effective in treating the condition it was designed to treat. Whether it has side effects or not isn't really relevant to that.

-t

[513852276]

For McKinley, the assumption he made is "Placebo will have less (or more, but 'more' is unlikely in this case) various of effects on patients' bodies compare to drugs", and "We will detect this difference" then aware of whether patients are getting the drug or a placebo. So, we will not able to perform double-blind study.

The flaw here is to overlook the possibility that placebo and drugs may play the same effect. Hence, Engle says "the outcome is actually undecided, how could you deny the double-blind study by assuming a definite difference? "

Let's look at Engle's assumption. Engle must assume the "It is possible that placebo and drugs could have the same effect on patient bodies". However, as placebo has no "side effects" (a reasonable assumption here), if drugs has any "known side effect", as mentioned in answer D, then the effects between placebo and drugs will not be the same ("being the same" requires both in "level" and in "types"). Hence, Engle,must interpret McKinley' remarks to be referring to "therapeutic effect" (could be the same), rather than "any known side effects" (placebo has no side effect, so a "absolute difference").

The only thing we need to assume by selecting choice D, is that "Placebo has no side effects, but have some therapeutic effects". The question asks us to select "most likely" interpretation, rather than "must be true" interpretation. Compared to the other choices, answer D's assumption is indeed the least strict one.

Hope this helps. Good luck in LSAT!

Hey guys,

Sorry, I'm still having some confusion with this problem.

Even if Engle had assumed that McKinley was referring to side effects, I still don't see how his conclusion would be affected. Isn't McKinley just saying that we can't foreclose the option of a double blind study because we don't know if various effects - regardless of whether they are therapeutic or side effects - will actually manifest themselves during the course of the study?

I don't think outcome as it is stated in the conclusion is just about "whether the drug works." When pharma companies talk about "outcome," they generally consider not only whether the drug will work, but also whether there will be any side effects in the first place.

Am I missing something here? Thanks!

[mydota]

Hi, I still have a question. I don't think when testing a drug, researchers are only focused on the therapeutic effects but rather on whatever affects the drugs has on patients.

So, let's assume Drug A, which reduces blood pressure, but have a side affect of turning patients skin to a reddish color.

Thus, what McKinley would refer here would be: look, we can't use double blind study because we would know who is getting the drug by looking at the effect (eg: reddish skin).

Then, Engle's reply can be interpreted as: You are assuming you the the result of the study, which is the drug would turn the patients' skins red. In this case, Engle is referring to the side effect.


Can someone find the flaw in this analogy?

[pewals13]

Keep in mind that Engle is saying that Mckinley assumes the outcome of a "double blind study." I think we can make a common sense inference that a double blind study will determine the efficacy of the drug being administered.

Does Engle's argument (conclusion ommitted) make more sense like this:

1) McKinley is assuming the drug will have side effects
---->
He is assuming he knows the outcome of the study

Or

2) McKinley is assuming the drug will have therapeutic effects
----->
He is assuming he knows what the outcome of the study will be

[pewals13]

One more point on (B):

Its extreme language should raise a red flag. Is Engle interpreting McKinley's remarks to mean the placebo will have NO effects at all? (ie. If it's a sugar pill that it could not increase glucose levels temporarily) Is this something that Engle most likely interpret's McKinley statement to mean?

[Aquamarine]

I still don't understand why C can't be an answer.
McKinley said the drug will have various effects on the patients' bodies. But he also said it will make us aware of "whether the patients are getting the drugs or a placebo" (Does it mean McKinley thought the placebo will produce no effects just like answer choice C?). So that's why I thought Engle said Mckinley assumed what the outcome of the study will be since McKinley said various effects of the drug AND whether the patients are getting the drugs or a placebo.

So can C be an answer?
Can anyone explain me why C can't be an answer and D is better?

Thanks!

[maryadkins]

The problem with (C) is that we don't know what McKinley OR Engle actually thinks with regard to it. McKinley never said or suggested NO effects whatsoever. He just says they'll have different effects. "No" effects is much more extreme. And accordingly, we don't know that Engle thinks McKinley thinks this! Engle just says, hey! You don't know that they won't work the same! That doesn't mean he thinks McKinley thinks the placebo will have no effects at all (and "no effects whatsoever" means all effects, not just positive or beneficial ones).

[HughM388]

Hey Deedub,

I thought I just answered that! : )

The outcome, as described here, would be whether or not the drug works to cure the underlying condition. Remember, the point of a drug test is to see if the drug is effective in treating the condition it was designed to treat. Whether it has side effects or not isn't really relevant to that.

-t

"Remember, the point of a drug test is to see if the drug is effective in treating the condition it was designed to treat. Whether it has side effects or not isn't really relevant to that."

Really? In what universe? The determination of side-effect profile is as important a part of trialing a new drug as anything else. If a drug appears to treat a condition but at the same time melts body tissue or causes people to go insane, it's pretty "relevant," and the drug is determined to be ineffective. We could, at this moment, successfully eradicate all disease-causing bacteria in the body, by boiling them to death, but the side-effects would be fairly gruesome—and relevant.

Meanwhile, I'm not sure how or why Engle would assume that McKinley was referring to "known side-effects" when the drug is explicitly described as being new.