Logical Reasoning

PT120 · S3 · Q19 Although high cholesterol levels have

A free, expert breakdown of this official LSAT Logical Reasoning question.

Save & drill this skill — build targeted practice sets from questions like this one
Video walkthroughs — watch every question solved step by step
81 official LSATs — as questions, timed sections & full-length tests

Although high cholesterol levels have been associated with the development of heart disease, many people with high cholesterol never develop heart disease, while many without high cholesterol do.

Conclusion

There is no reason for anyone to make dietary changes for the sake of preventing heart disease.

Evidence

Dietary changes that affect cholesterol levels have no effect on lipoprotein(a) levels (and lipoprotein-a seems to sometimes be a cause of heart disease).

Evaluate

This is a weird argument, to say the least. The first sentence doesn't seem involved in the author's reasoning at all. She makes an incredibly over-strong conclusion by saying NO reason for ANYONE to make dietary changes for the sake of heart disease.

That should strike us terrible advice. Could I cut down on my alcohol intake and possible lower my risk of heart disease? What about all the fat I'm eating clogging my arteries?

She singles out one possible way you might lower your heart disease risk (lowering your lipoprotein-a levels), tells us that dietary changes have no affect on that, and then concludes that dietary changes are useless for the sake of preventing heart disease.

Goal

It seems like this author is thinking that lipoprotein(a) is the only way that dietary changes could have helped lower your risk of heart disease.

But what if there are other dietary changes you could make that would lower your heart disease risk some other way?

19.

Which one of the following most accurately describes a flaw in the argument?

It fails to consider the
Not an Objection
Would is hurt the argument if lipoprotein(a) raises cholesterol levels? Would that give us a way to argue that, "there are dietary changes you can make that affect heart disease?" No, it wouldn't, since the author already established that dietary changes have no affect on lipoprotein(a) levels.
20% picked this
It provides no evidence for
Not True
It does provide evidence: recently, they found higher than average lipoprotein(a) levels in people who had heart disease but didn't have any other underlying condition to which to attribute the heart disease.
13% picked this
Correct
It presents but ignores evidence
Why this is right
The first sentence says that "high cholesterol is associated with the development of heart disease". Associated with is the same as correlated with, which means that there's a statistical lumpiness that keeps putting high cholesterol and heart disease in the same room with each other. Correlations almost always have exceptions (statisticians measure the strength of the correlation based on what percentage of cases adhere to the correlation vs. vary from it). The second half of the first sentence explains that the correlation between high cholesterol and heart disease is not a perfect one. There are many examples of high cholesterol with no heart disease, and many examples of heart disease with no high cholesterol. Correlations are by no means proof of causality, but they are evidence there may be causality. If you saw that 85% of people with lung cancer were smokers, even though it's not 100% of smokers or 100% of lung cancer patients, you'd be wise to surmise that there might be some link between lung cancer and smoking. So this answer is pointing out the objection that, "Maybe dietary changes don't lower your lipoprotein(a), which may be a cause of heart disease, but they can lower your cholesterol levels, and high cholesterol may be a cause of a heart disease!" This is a subtle example of the famous flaw Internal Contradiction, in which the author says something early on in the paragraph that seems to undermine something they say later.
Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.
60% picked this
It fails to consider the
Out of Scope
Out of Scope: other than heart disease If the conclusion had merely said, "Hence, there is no reason for anyone to make dietary changes", then it would have been vulnerable to the objection of, "Hey, just cuz it does nothing for heart disease doesn't mean it doesn't do good when it comes to other health problems." But this conclusion explicitly narrowed its scope to "for the sake of preventing heart disease".
5% picked this
It offers no explanation for
Not Necessary
Did the author need to offer an explanation for why some people with high cholesterol never get heart disease? No. She's saying that dietary changes aren't going to do anything to prevent heart disease, so she's presumably thinking that there isn't a causal connection between high cholesterol and heart disease. She would only be burdened by needing to explain these "exceptional cases" if she were trying to sell us on the idea that high cholesterol does cause heart disease.
2% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill

LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free