People with a certain medical condition tend to have lower levels of

Question

People with a certain medical condition tend to have lower levels of low-density lipoprotein cholesterol (LDL-C) before they are diagnosed with this condition than do people without this condition. This association is equally strong whether or not the individuals have taken medications to lower their LDL-C. Therefore, having taken such medications does not make it more likely that people with lower LDL-C will develop the condition in question.

The doctor’s argument is most vulnerable to criticism on which of the following grounds?

A. It presumes that if a medication to lower LDL-C does not strengthen the association between lower LDL-C and a medical condition, the medication does not help cause the condition.

B. It confuses a claim about a medication’s effects with a claim about the effects of a condition the medication is intended to treat.

C. It takes for granted that a factor that is not known to cause a given effect cannot cause another effect associated with the first.

D. It overlooks the possibility that even if one factor does not cause another, they may be strongly associated.

E. It takes for granted that if two factors are associated with each other whenever a third factor is absent, the association can also hold even when that third factor is shown to be present.

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Official Answer

A

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MartyMurray · Accepted Answer

People with a certain medical condition tend to have lower levels of low-density lipoprotein cholesterol (LDL-C) before they are diagnosed with this condition than do people without this condition. This association is equally strong whether or not the individuals have taken medications to lower their LDL-C. Therefore, having taken such medications does not make it more likely that people with lower LDL-C will develop the condition in question.

The conclusion of the argument is the following:

having taken such medications does not make it more likely that people with lower LDL-C will develop the condition in question

The reasoning of the argument is basically that, since the association between having low LDL-C and being diagnosed with the condition is the same regardless of whether people have taken medications to lower LDL-C, the medications don't help to cause people to develop the condition.

The doctor’s argument is most vulnerable to criticism on which of the following grounds?

This question is a Logical Flaw question, and the correct answer will describe an aspect of the argument that's a flaw.

A. It presumes that if a medication to lower LDL-C does not strengthen the association between lower LDL-C and a medical condition, the medication does not help cause the condition.

The choice perfectly describes a flaw in the argument.

After all, the argument uses one premise, that the association betwen LDL-C and the condition is the same regardless whether the person experiencing the condition used medications, to support the conclusion that medications do not help to cause the condition.

That the argument does so is a flaw because, even if medications don't affect that particular assoication, they could still cause the condition. After all, they could cause the condition without affecting that association. So, the fact that medications don't change that association doesn't necessarily mean that they don't help to cause the condtion.

Thus, we could say that, in presuming that if medications do not strengthen the association, they don't help to cause the condition, the argument makes an unwarranted assumption.

Keep.

B. It confuses a claim about a medication’s effects with a claim about the effects of a condition the medication is intended to treat.

This choice is incorrect because the argument simply doesn't do what this choice says.

After all, the argument doesn't mention the effects of the condition and doesn't confuse the effects of medications with the effects of the condition. Rather, it keeps clear the effects of medications, which are to lower LDL-C and, possibly, to help cause the disease.

Eliminate.

C. It takes for granted that a factor that is not known to cause a given effect cannot cause another effect associated with the first.

Let's break this choice down to see why its incorrect:

a factor that is not known to cause a given effect

The only factor that the passage mentions as not being known to cause an effect is "taking medications," which the passage claims "does not make it more likely that people with lower LDL-C will develop the condition in question."

On the other hand, "taking medications" to lower LDL-C would obviously be known to cause "low levels" of LDL-C.

another effect associated with the first

The only two "associated" effects mentioned in the passage are the "condition" and "low levels" of LDL-C., and "the first" would be the one that "taking medications" is not known to cause, meaning "another effect" must be "low levels" of LDL-C.

So, let's now translate this choice to make it specifically about this passage.

It takes for granted that a factor (taking medications) that is not known to cause a given effect (the condition) cannot cause another effect (low levels of LDL-C)  associated with the first (the condition).

Having translated the choice, we see that it basically says that the argument takes for granted that "taking medications" does not cause "low levels" of LDL-C.

Since, clearly, the passage does not say or imply that taking LDL-C lowering medications does not cause low levels of LDL-C, this choice is incorrect.

Eliminate.

D. It overlooks the possibility that even if one factor does not cause another, they may be strongly associated.

It's true that the argument does not address the possibility that, even if medications do not cause the condition, medications and the condition may be associated.

At the same time, the fact that the argument does not address that possibility is not a flaw in the argument. After all, as long as medications do not cause the condition, the conclusion is correct, regardless of whether medications and the condition are strongly associated.

Eliminate.

E. It takes for granted that if two factors are associated with each other whenever a third factor is absent, the association can also hold even when that third factor is shown to be present.

This choice is incorrect because the argument doesn't take for granted, i.e., assume, that the association between low LDL-C and the condition holds when medications are present. Rather, it states as fact that "this association is equally strong whether or not the individuals have taken medications to lower their LDL-C."

Something the argument states as fact is not something the argument takes for granted, or assumes.

Eliminate.

Correct answer:  A

sayan640 · Answer

Hi  gmatknight   MartyMurray   egmat  , Will you please explain why option C is incorrect ?

Posted from my mobile device

MartyMurray · Answer

I've updated the explanation for (C). See whether you understand why it's incorrect now.

AdjustedEbitdad · Answer

I'm not an expert, but see if this answers your question. Not even sure if it's 100% correct (It generated post-Socratic dialogues with ChatGPT) - https://gmatclub.com/forum/download/file.php?id=84471 GMAT-Club-Forum-vkct0uh5.png

KarishmaB · Answer

Certainly a challenging question, especially under time pressure. Premises: People with a certain medical condition (let's call it CON) tend to have lower levels of LDL-C before they are diagnosed with this condition than do people without this condition. People who have CON, have lower levels of LDL-C before being diagnosed - may be after diagnosis, they are given medicines to increase LDL-C that is why the argument specifies 'before being diagnosed'. Say 60% people with lower LDL-C develop CON. This association is equally strong whether or not the individuals have taken medications to lower their LDL-C. Think of the correlation between CON and low LDL-C. We are given that whether low LDL-C was caused by taking some medicines (may be to counter high LDL-C) or naturally, the correlation between CON and low LDL-C is the same. We don't see that people who take medicine to lower LDL-C get CON more often. It remains 60% only. That low LDL-C, either natural or medicine induced, has same level of correlation with CON. Conclusion: Having taken such medications does not make it more likely that people with lower LDL-C will develop the condition in question. Author concludes that medicine to lower LDL-C does not make it more likely to develop the condition. This is flawed, right? After all, a person's chance of getting CON may be 1% but after taking the medicine to lower LDL-C, it may have increased to 60% now. The doctor’s argument is most vulnerable to criticism on which of the following grounds? A. It presumes that if a medication to lower LDL-C does not strengthen the association between lower LDL-C and a medical condition, the medication does not help cause the condition. Correct. It does presume that just because the chance of getting CON with medicine induced low LDL-C is still 60%, the medicine doesn't cause CON. But the previous probability of getting CON for the person could have been much lower. The medicine could have been the cause. All other options are simply words from the argument put together in some order to confuse us. B. It confuses a claim about a medication’s effects with a claim about the effects of a condition the medication is intended to treat. Most likely the popular incorrect answer. a claim about the effects of a condition the medication is intended to treat - the claim is that LDL-C causes CON. The author does not assume that the medicine causes CON. Contrary in fact. C. It takes for granted that a factor that is not known to cause a given effect cannot cause another effect associated with the first. We don't have any 'a factor that is not known to cause a given effect.' What factor is not known to cause which effect? D. It overlooks the possibility that even if one factor does not cause another, they may be strongly associated. He only claims that one factor does not cause the other. He does not claim that 'hence they are not strongly associated.' E. It takes for granted that if two factors are associated with each other whenever a third factor is absent, the association can also hold even when that third factor is shown to be present. The premises tell us that that the association is the same whether the third factor (medicine) is present or not. The author's conclusion has no such flaw. Answer (A) Here is a discussion on another flaw in logic question: https://youtu.be/Mk_-ONJKmz4

Goldenfuture · Answer

Low LDL is naturally associated with disease.
Meds lower LDL artificially, but the correlation between low LDL and disease stays the same.
SO the doctor says for a patient that artificially lowered it's LDL their prob of getting disease does not increases.

Just becuase correlation remained same - possibility to cause disease should increase as one moves from High LDL to low LDL with medicines. With this only A makes any sense

liberoasperiores · Answer

So true. These options took time to decode.

People with a certain medical condition tend to have lower levels of

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People with a certain medical condition tend to have lower levels of

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