When people show signs of having a heart attack an electrocardiograph

Question

When people show signs of having a heart attack an electrocardiograph (EKG) is often used to diagnose their condition. In a study, a computer program for EKG diagnosis of heart attacks was pitted against a very experienced, highly skilled cardiologist. The program correctly diagnosed a significantly higher proportion of the cases that were later confirmed to be heart attacks than did the cardiologist. Interpreting EKG data, therefore, should be left to computer programs.

Which one of the following, if true, most weakens the argument?

(A) Experts agreed that the cardiologist made few obvious mistakes in reading and interpreting the EKG data.
(B) The practice of medicine is as much an art as a science, and computer programs are not easily adapted to making subjective judgments.
(C) The cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program.
(D) In a considerable percentage of cases, EKG data alone are insufficient to enable either computer programs or cardiologists to make accurate diagnoses.
(E) The cardiologist in the study was unrepresentative of cardiologists in general with respect to skill and experience.

Source: LSAT

KarishmaB · Accepted Answer

Computer program vs Cardiologist - EKG diagnosis
The program correctly diagnosed a significantly higher proportion of the cases that were later confirmed to be heart attacks than did the cardiologist.

Conclusion: Interpreting EKG data, therefore, should be left to computer programs.

The argument tells us that the program performed better in cases which resulted in heart attacks. IT is then concluding that computers are better at interpreting data.

What can weaken this? What if the cardiologist performed better in cases which resulted in no heart attacks? What if she was able to better interpret the data in those situations? Then can we say that computers are better at interpreting data? No. We need to see overall results to find out who/what did a better job.

(A) Experts agreed that the cardiologist made few obvious mistakes in reading and interpreting the EKG data.

Well, if even a highly skilled cardiologist made mistakes, computer might be better at it. Does not weaken our conclusion.

(B) The practice of medicine is as much an art as a science, and computer programs are not easily adapted to making subjective judgments.

Irrelevant. We are talking about our conclusion based on our study.

(C) The cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program.

Correct. As discussed above.

(D) In a considerable percentage of cases, EKG data alone are insufficient to enable either computer programs or cardiologists to make accurate diagnoses.

Irrelevant. We are talking about who can make a better call based on EKG data alone.

(E) The cardiologist in the study was unrepresentative of cardiologists in general with respect to skill and experience.

We know that the cardiologist in the study was highly skilled. If he was unrepresentative of cardiologists in general, it means general cardiologists are not this skilled. If even he could not do a better job than the computer, then it does seem that the job should be left to the computer.

Answer (C)

Here are some discussions on weaken questions:
https://youtu.be/EhZ8FKkfy0k
https://youtu.be/tnFX99OpyYs
https://youtu.be/XCBp62o70Eg
https://youtu.be/55QgRwZmFRo

mitravanu · Answer

When people show signs of having a heart attack an electrocardiograph (EKG) is often used to diagnose their condition. In a study, a computer program for EKG diagnosis of heart attacks was pitted against a very experienced, highly skilled cardiologist. The program correctly diagnosed a significantly higher proportion of the cases that were later confirmed to be heart attacks than did the cardiologist. Interpreting EKG data, therefore, should be left to computer programs.

Which one of the following, if true, most weakens the argument?

(A) Experts agreed that the cardiologist made few obvious mistakes in reading and interpreting the EKG data.  The ''obviousness'' of the mistakes is not properly defined.  
(B) The practice of medicine is as much an art as a science, and computer programs are not easily adapted to making subjective judgments.  No evidence is provided to support that subjective judgement played any part in the diagnostics. 
(C) The cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program.  This is correct as it provides evidence of cardiologists being better than the computer program in another aspect of the diagnostics. 
(D) In a considerable percentage of cases, EKG data alone are insufficient to enable either computer programs or cardiologists to make accurate diagnoses.  Sufficiency of EKG data isn't in the scope of conclusion.  
(E) The cardiologist in the study was unrepresentative of cardiologists in general with respect to skill and experience.  The word highly skilled already makes the cardiologists unrepresentative. This actually strengthens the conclusion.

Anc: C

RohitSaluja · Answer

Hi experts  VeritasKarishma   GMATNinja  , can you please help me here.

The conclusion for the above argument is computers are better off than cardiologists to interpret EKG data and the reasoning it provides is that "computers diagnosed higher no. of cases that were later confirmed to be heart attacks". Now I was divided b/w C and E.

Option C says "cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program" but still the cardiologist fail to diagnose the cases which were later confirmed to be a heart attack

Option E says the cardiologist in the study had a skill level less than the general/average, cardiologist undermines the study itself questioning in the validity of the claim, thus damaging the argument. So isn't E the better option in this case?

RohitSaluja · Answer

Thanks for the prompt response Karishma, I missed the highly skilled/experienced part in the argument. It makes so much more sense now. Appreciate the help!

CEdward · Answer

I will admit, I am not the biggest fan of this question...there are several interesting contenders and C doesn't fully satisfy me.

When people show signs of having a heart attack an electrocardiograph (EKG) is often used to diagnose their condition. In a study, a computer program for EKG diagnosis of heart attacks was pitted against a very experienced, highly skilled cardiologist. The program correctly diagnosed a significantly higher proportion of the cases that were later confirmed to be heart attacks than did the cardiologist. Interpreting EKG data, therefore, should be left to computer programs.

Which one of the following, if true, most weakens the argument?

(A) Experts agreed that the cardiologist made few obvious mistakes in reading and interpreting the EKG data. X 
-eliminated this one b/c we're not allowed to counter premises on the GMAT
(B) The practice of medicine is as much an art as a science, and computer programs are not easily adapted to making subjective judgments. X
-also true, and a compelling reason why we might opt against EKGs...but I eliminated b/c this is in some senses vague.
(C) The cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program. (Possibly correct)
-this choice makes the assumption that the deficits in skill with respect to identifying actual heart attacks is less important than identifying true false negatives...there's nothing to suggest that we should lean one way or the other really (either for or against EKGs) since these are both important aspects of medicine
(D) In a considerable percentage of cases, EKG data alone are insufficient to enable either computer programs or cardiologists to make accurate diagnoses. X
(E) The cardiologist in the study was unrepresentative of cardiologists in general with respect to skill and experience. (Possibly correct)
-a sample size of one is certainly not representative...in fact it's not even a sample size at all ...and in statistics, 1 more often than not, means 0 (of course there are exceptionally rare diseases for example which count as substantive cases).

Foreheadson · Answer

As always, LSAT CR questions bring something entirely different from GMAT.

Either the patient has Heart attack, or not. So if computer recognizes more cases of heart attack, how come doctor recognizes more cases where heart attack is absent.

I find LSAT more and more useless as time passes

Posted from my mobile device

Shikhar22 · Answer

Hello  AndrewN

Hope you had a good weekend!

For the first time, I think the OA is pretty questionable. Option C states that “The cardiologist correctly diagnosed a significantly higher proportion of the cases in which no heart attack occurred than did the computer program”

I argued against this option as it states nothing about the diagnosis of the ‘EKG report’, around which the conclusion is based. And unfortunately, I eliminated it. Am I being too pedantic? I went for E, which, I reckoned, attacks the underlying assumption.

Would love to hear your views on this. Thank you in advance!

Posted from my mobile device

AndrewN · Answer

Hello,  Shikhar22 . Thank you for the well wishes. I hope the same for you. In the question at hand, I am afraid I agree with the OA. The exact argument given is that  interpreting EKG data should be left to computer programs   . The grounds for the suggestion are that  the   program correctly diagnosed a significantly higher proportion of the cases that were later confirmed to be heart attacks than did the cardiologist . Our goal is to cast doubt on the notion that cardiologists ought to be pushed aside when it comes to interpreting EKGs.

Answer choice (E) is problematic because the passage tells us that the cardiologist in the trial was  highly skilled . If this highly skilled cardiologist was  unrepresentative of cardiologists in general with respect to skill and experience , we cannot assume that other cardiologists would be either more or less skilled. Perhaps other cardiologists, in general, are  less  skilled, and the argument could hold. We simply have nothing to lean on.

By contrast, answer choice (C) allows us to appreciate that a qualified cardiologist might be better to keep around when it comes to interpreting EKG data. You are correct that the EKG report is not mentioned directly, but we are left to wonder, then, how the cardiologist  diagnosed  something—in fact, the very criterion (a diagnosis) used in the comparison. If the cardiologist outperformed the computer program with one type of diagnosis based on an EKG report, then we have a compelling reason to doubt the argument. Choice (C) is a perfectly qualified answer.

I tend to be more careful on LSAT Logical Reasoning questions than on Critical Reasoning questions, since the former tend to present finer points to consider or debate within the answer choices; even so, I took just over two minutes on this one. None of the other answer choices fit the given argument. (I could not care less about what  experts agreed  on in answer choice (A), for example. A subpar human interpretation of an EKG could still be worse than the reading the computer program had given, not to mention that I take no comfort in  few . Why would a highly skilled cardiologist make even one  obvious  mistake. Yikes!)

I hope that helps resolve your doubts on this one. Thank you for thinking to ask.

- Andrew

IanStewart · Answer

It seems a few people aren't too persuaded by the OA here, but the answer is unambiguously C. Anyone could do better than an expert cardiologist if judged solely by the metric in the question stem. You could just say, looking at every EKG, "yup, that was a heart attack". Then every time the EKG actually was from a heart attack, you'd be right. You'd also be wrong every time it wasn't from a heart attack, but the question stem isn't judging the computer's wrong answers, only its right ones. That's why we need some information about how often the computer was right in cases when a heart attack didn't happen, or else we have no way to know if the computer is just saying "heart attack" way too often, or if the computer is genuinely good at diagnosing heart attacks from EKGs.

moshe1234 · Answer

IanStewart  This question seems to weigh the importance of minimizing false positives against minimizing false negatives. As other commenters already pointed out, there's no apparent reason to value one over the other.

Additionally, while it is true that the passage does state that the cardiologist in question was "highly trained and experienced" - these words are relative! Highly trained compared to whom? Again, as other commenters pointed out, the fact that a recomendation is being made on the basis of a statistic of only 1 person (!) is something to be challenged.

The best I could come up with is an idea seemingly not yet proposed by others here:

The passage claims that humans should be replaced by computers - the negation of this would be that humans would not be replaced by computers but rather would  work together .

So we are looking for a reason to defend the idea that they should work together rather than one replacing the other, in which case option C indeed becomes attractive.

IanStewart · Answer

I think you're rephrasing the question. The question asks which answer choice weakens the argument. It does not ask which choice  destroys  the argument. The stem tells us computers are more accurate than people in one situation. The argument concludes that we should replace people with computers. We have reason to question that argument if we learn people are more accurate than computers in a different situation. The conclusion becomes less compelling, and the argument is weaker. That is why C is correct. Answer C does not make the argument  wrong  -- with more information, we might think the conclusion is still correct -- but answer C casts doubt on the conclusion, while no other answer choice does.

I think you'll also find your success rate on GMAT CR questions improves if you change your approach in these ways:

You should take the premises of a GMAT CR argument to be facts as written, according to their ordinary meaning. If an argument tells you that someone is an expert, you will not be spending your time well if you ask "expert relative to whom?" Or if a question says a cardiologist is "highly trained and experienced", that argument is trying to tell you that the person is a genuinely good cardiologist. There's no reason to ask "highly trained relative to whom?" If we could not trust CR question stems to mean what the average reader would expect them to mean, we couldn't answer any CR questions at all.

Your task, in a weaken question, is not to find an answer choice that would justify some alternative conclusion that you invent. Any time you spend imagining new conclusions will be wasted time. You only want an answer choice that makes the stated conclusion less compelling. The right answer is C here not because C makes a hybrid computer-person diagnostic team the best option (we have no way to know that, as I explained in my previous post -- the computer in this question could be genuinely terrible at diagnosis). The answer is C because if answer C is true, it is not as clear that computers are better than people at heart attack diagnosis.

XLmafia21 · Answer

Hi Karishma
Hope you are doing well.

My question is - had the stimulus not mentioned about the skill level of the cardiologist, would that qualify E over C?

KarishmaB · Answer

(C) is a weakener. Hence it will remain the answer. A correct GMAT question will not give two weakeners.

If the stimulus did not mention 'highly skilled cardiologist' then the study's results would be irrelevant. We would not know how the skill level of typical cardiologists compare to the cardiologist in the study. Then if the cardiologist in the study was more skilled than avg, it would strengthen our conclusion but if he were less skilled than average, then it would weaken our conclusion.

arushi118 · Answer

KarishmaB

Here how do we decide - that what matters more - false negatives or false positives?

When people show signs of having a heart attack an electrocardiograph

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GMAT Critical Reasoning (CR) Questions

When people show signs of having a heart attack an electrocardiograph

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