#20 - When people show signs of having a heart attack an

[Administrator]

Complete Question Explanation

Weaken. The correct answer choice is (C)

In this case, a computer program and a very experienced, highly skilled cardiologist are compared on
the basis of the quality of their diagnoses. The computer was significantly better at true heart attack
diagnoses, which by extension means that the cardiologist under-diagnosed a number of actual heart
attacks. While this is an important metric (since underdiagnosing might result in inadequate care), it
is not the only measure of quality. It is also important to avoid over-diagnosing, since concluding that
someone is suffering a heart attack incorrectly could result in expensive treatments, hospital stays,
or even dangerous surgeries. A good diagnostician avoids both over- and under-diagnosis, which the
argument does not address.

Answer choice (A): If it is true that the cardiologist did not make obvious mistakes but still underdiagnosed,
then there is little reason to believe that another cardiologist would perform better. (A)
supports that conclusion that interpreting EKG data should be left to computer programs.

Answer choice (B): Determining if a patient has had a heart attack is not subjective—it either
happened or it did not. The data may be difficult to interpret and experts may even disagree over
what the data suggest, but that does not mean the judgment is subjective, only challenging. (B) does
not weaken the stimulus.

Answer choice (C): This is the correct answer choice. For the reasons suggested above, it is
important to avoid over-diagnosis, as well as under-diagnosis. If (C) is true, then the computer
program was more likely to diagnose heart attacks which did not occur than the cardiologist. Thus,
both the computer program and the cardiologist have weaknesses in interpreting EKG data, but it
would be unwise to leave interpreting entirely to computer programs.

Answer choice (D): Suggesting that both the computer program and cardiologist failed to diagnose
a considerable percentage of cases does not outweigh the fact that the cardiologist was significantly
more likely to under-diagnose than the computer program. So, in some cases, neither solution is
adequate, and in the remaining cases, the computer is superior. This suggests that interpreting EKG
data should be left to computer programs.

Answer choice (E): We are told in the stimulus that the cardiologist was highly skilled and very
experienced. If (E) is true and other cardiologists are unlikely to be as skilled or experienced, then
it is probable that they would perform even worse than this cardiologist did. Thus, the author’s
argument is strengthened, not weakened, by this answer choice.

[beniakc]

#20 2nd section of test (1st LR sec)
Why is B incorrect?

Why is C correct?

It appears that while C would weaken (in this case make it a wash), B weakens the question the most.

[Steve Stein]

Here a computer program's results are compared with those of a cardiologist in diagnosing heart attacks based on EKGs. The computer program was able to correctly diagnose heart attacks in a higher proportion of cases, so the author makes the broad conclusion that interpreting all EKG data should be left to computer programs.

Answer choice B deals with the entire practice of medicine, which is in part an art and in some cases includes the need for subjective judgment. The author's argument is much more limited, though, and it is unclear how much subjective judgment comes into play when interpreting EKGs.

Answer choice C weakens this conclusion by providing another consideration: if the cardiologists were more successful at diagnosing the non-heart attack cases--that is, all other cases , then this significantly weakens the author's broad conclusion that all EKG diagnosis should be left to computer programs.

Tough question; please let me know whether this is clear--thanks!

~Steve

[bli2016]

Hi, I just wanted to double check that I understand the explanation above. So if the conclusion was broader, like "interpreting MEDICAL data, therefore, should be left to computer programs", would answer B be correct? In other words, is it because of the phrase in the conclusion (last sentence of the stimulus) that specifies that the author is only talking about EKG data, that makes answer B incorrect? Thanks!!

[AthenaDalton]

Hi bli2016,

You correctly zeroed in on the fact that answer choice (B) doesn't fit with the conclusion in the stimulus which says that "interpreting EKG data" should be left to machines. Given that big mismatch between "the practice of medicine" and "interpreting EKG data," answer choice (B) is an easy one to eliminate.

However, even if answer choice (B) were phrased as you suggested, it still wouldn't be the best answer choice.

The stimulus uses somewhat tricky language in saying that:

The computer program beat the doctor in diagnosing cases that heart attacks

By contrast answer choice (C) tells us that:

The doctor beat the computer program in diagnosing cases that not heart attacks

Essentially, the computer excels in one area of diagnoses ("heart attacks") and the doctor excels in the other area of diagnosis ("not heart attacks"). What we really need to be able to assess anything about the overall success rate of the doctor's or the computer program's diagnosis is the proportion of cases that end up resulting in heart attacks or not. We really have no idea, based on the stimulus, whether the doctor or the computer program got a greater percentage of diagnoses correct.

To be clear, if 90 out of 100 cases fall into the "heart attack" category the computer program would be the clear winner in making the most accurate diagnoses. But if 90 out of 100 cases ended up not being heart attacks, the doctor would have the overall better track record.

Answer choice (C) is best because it directly undermines a key premise in the argument. By contrast, answer choice (B) provides a new generalization for which there isn't much support in the prompt. If anything, the prompt indicates that in at least one area of medicine (interpreting EKG charts), computer programs may be better than doctors at one specific task.

I hope this makes sense!

Athena Dalton

[jbrown1104]

Hello PS!

I am going over this PT. During timed conditions I selected (E). During untimed I narrowed down to (D) and again (E). It seems like Weaken questions are giving me the most grief. I understand we should be suspicious of the stimulus and accept the answer choices as true but some questions I feel as though we are expected to assume outside knowledge which in some cases can hurt a test taker or help.

In this case, I think I understand why (C) is correct but would like to verify my reasoning. So, the conclusion states "interpreting EKG data should be left to computers". The key here is how "interpreting" is used in the conclusion. The study only looked at interpreting EKG scores correctly, but the conclusion generalises interpreting as a whole (which includes interpreting correctly and incorrectly). This gap can be weakened by showing despite diagnosing less patients successfully the cardiologist had a higher success in diagnosing when no heart attack occurred and that too is an important part of interpreting.

So, I have noticed that for a lot of weaken questions an author will talk about one thing in their evidence and then make a general blanket statement conclusion. OR the author will say "it can be x and y" but conclude "it was y". Both have gaps that can be filled by showing that the general conclusion has a an exception or that it was the opposite of what was concluded (i.e. it was "x and not y"), respectively. Is this a safe format to consider when attacking these questions?

Thanks!
~JB

[Adam Tyson]

That is certainly one way to look at a lot of strengthen and weaken questions, JB! Gaps, overgeneralizations, conclusions that bring in new information - these are all fertile ground for these sorts of questions, and spotting them can help you prephrase and select the correct answer more quickly, confidently, and accurately.

As to answer E, which got you and almost a second time, consider that the stimulus told us the doctor in the study was "a very experienced, highly skilled cardiologist." If he is not representative, then perhaps that means other doctors are less skilled and/or less experienced? That would make the argument stronger, not weaker!

[hrhyoo]

Hi Powerscore,

I selected D because I misread it as EKG data alone aren't sufficient for just computer programs to make accurate diagnoses. I don't know why or how I skipped over "cardiologists" in that AC. However, as I was reviewing the question, I crossed out C as outside the scope thinking the subject matter in this stimulus as diagnosing heart attacks, not diagnosing no heart attacks.

In the LSAT, I noticed that when the stimulus is talking about, say for example, saving money, any answer choices discussing not saving money would be incorrect. So for this particular question, why is it okay to talk about no heart attacks when the focus is heart attacks?

Thanks in advance.


Hanna

[KelseyWoods]

Hi Hanna,

It really depends on what type of question you have and what your argument is...you can't just blindly eliminate all answer choices that negate something in your stimulus--for some questions you want an answer choice that negates something in the stimulus!

In this case, we are being asked to weaken a conclusion that states that interpreting EKG data should be left to computer programs. This is based on the premise that the computer was more accurate at diagnosing heart attacks. But our conclusion is not just about diagnosing heart attacks--it's about interpreting EKG data more generally. So answer choice (C) weakens it because it says that maybe the computer was better at using EKG data to diagnose heart attacks, but the cardiologist was better at using EKG data to diagnose non-heart attack cases. It weakens the conclusion that computers are better at interpreting EKG data overall by stating that in non-heart attack cases, the cardiologist was actually better at interpreting the data.

Remember to focus on the conclusion in Weaken questions so that you know exactly what it is you're supposed to be attacking. Also remember that there are no hard and fast rules for eliminating answer choices on this test. It's a tricky test, full of subtleties and unfortunately there are no quick and easy shortcuts!

Hope this helps!

Best,
Kelsey

[hrhyoo]

Hi Kelsey,

Thank you for your explanation. I totally understand it now. You are right when you said it is about diagnosing heart attacks in general, not just about figuring out who has a heart attack. It should include finding out who doesn't have a heart attack. I limited the scope for no reason...

Thanks again,


Hanna