Critical Reasoning

Although this has been posted multiple times, I did not get answers to my doubts so I am reposting this.

Of patients over 65 years old who survived coronary bypass surgery-a procedure widely prescribed for people with heart disease-only 75 percent benefited from the surgery. Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense, were more interested in an opportunity to practice their skills and in their fee than in helping the patient.

Which of the following, if true, most seriously undermines the argument?

A.Many of the patients who receive coronary bypass surgery are less than 55 years old.

B.Possible benefits of coronary bypass surgery include both relief from troubling symptoms and prolongation of life.

C.Most of the patients in the survey decided to undergo coronary bypass surgery because they were advised that the surgery would reduce their risk of future heart attacks.

D.The patients over 65 years old who did not benefit from the coronary bypass surgery were as fully informed as those who did benefit from the surgery as to the risks of the surgery prior to undergoing it.

E.The patients who underwent coronary bypass surgery but who did not benefit from it were medically indistinguishable, prior to their surgery, from the patients who did benefit.

E

Hi Experts,

Please share your opinion on Option D and E. And why E is the correct option?

[email protected] wrote:Although this has been posted multiple times, I did not get answers to my doubts so I am reposting this.

Of patients over 65 years old who survived coronary bypass surgery-a procedure widely prescribed for people with heart disease-only 75 percent benefited from the surgery. Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense, were more interested in an opportunity to practice their skills and in their fee than in helping the patient.

Which of the following, if true, most seriously undermines the argument?

A.Many of the patients who receive coronary bypass surgery are less than 55 years old.

B.Possible benefits of coronary bypass surgery include both relief from troubling symptoms and prolongation of life.

C.Most of the patients in the survey decided to undergo coronary bypass surgery because they were advised that the surgery would reduce their risk of future heart attacks.

D.The patients over 65 years old who did not benefit from the coronary bypass surgery were as fully informed as those who did benefit from the surgery as to the risks of the surgery prior to undergoing it.

E.The patients who underwent coronary bypass surgery but who did not benefit from it were medically indistinguishable, prior to their surgery, from the patients who did benefit.

E

The conclusion: the doctors who recommended the surgery were doing so for selfish reasons (a chance to hone their skills/a chance to make $)
The premise: 25% of the patients undergoing the operation did not benefit.

The argument is asserting that the doctors, in some cases, knew that a patient was a bad candidate for the surgery, but recommended the procedure anyway. (Imagine a doctor evaluating a patient, thinking to herself, "yikes, there's no way this procedure will work," and then doing it anyway for the money.)

If we want to undermine that claim, we want to show that the doctors were not consciously thinking that some of these patients would make poor candidates for the procedure.

D is irrelevant. We're assessing the knowledge/motivation of the doctors, not of the patients.

E: If it were impossible to tell the difference between the patients who would benefit and those who wouldn't, then doctors couldn't possibly have been thinking to themselves that some of the patients were poor candidates for the procedure, as they looked just like the ones that benefited. So the scenario above, where the doctor is thinking to herself "bad candidate, but let's make some money!" is no longer plausible. E is the answer.

Hi David,

Appreciate your reply. I do understand what you are getting it. However, my confusion is the below in your explanation:

The argument is asserting that the doctors, in some cases, knew that a patient was a bad candidate for the surgery, but recommended the procedure anyway. (Imagine a doctor evaluating a patient, thinking to herself, "yikes, there's no way this procedure will work," and then doing it anyway for the money.)

Can you please guide me with the following:

1. How are we making the assumption that the doctors specifically selected the set to experiment on. What part of the argument is hinting towards a selected set? Please suggest.

2. What if the doctors decided to randomly experiment on patient? Then it doesn't weaken the conclusion.

I look forward to your response.

[email protected] wrote:Hi David,

Appreciate your reply. I do understand what you are getting it. However, my confusion is the below in your explanation:

The argument is asserting that the doctors, in some cases, knew that a patient was a bad candidate for the surgery, but recommended the procedure anyway. (Imagine a doctor evaluating a patient, thinking to herself, "yikes, there's no way this procedure will work," and then doing it anyway for the money.)

Can you please guide me with the following:

1. How are we making the assumption that the doctors specifically selected the set to experiment on. What part of the argument is hinting towards a selected set? Please suggest.

2. What if the doctors decided to randomly experiment on patient? Then it doesn't weaken the conclusion.

I look forward to your response.

Sure thing.

1. The key line is here: Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery were more interested in an opportunity to practice their skills and in their fee than in helping the patient.

So we know that the doctors are advising some people to get the surgery and others, presumably, not to. The question then, is why? Is it because the patient is a good candidate for the procedure or because the doctor wishes to make money? Put another way, is the doctor committing the indiscretion of advising some subset of patients to get the procedure even though she knows these patients are not good candidates? (If she can't tell the difference between good candidates and bad, this can't be the case.)

2. A very good question, but there's no evidence to suggest that the doctors would randomly select patients for the procedure. (In fact, if 75% of the patients are benefitting, that's actually evidence against the patients being randomly selected.) Look back at the relevant sentence: Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense, were more interested in an opportunity to practice their skills and in their fee than in helping the patient. So there are two possible motivations provided: selfishly boosting their incomes/experience or helping people. If the patients were selected randomly, there's be no evidence of any kind of motivation. Maybe think of it this way. If an argument posits: X is a better motivation than Y, there's no reason to consider Z, if Z isn't mentioned.

Great explanation David.

I have an off the topic question. I am trying to apply rules on CR and think through but haven't been able to see significant improvement. Is there something that you would suggest to improve my CR?

[email protected] wrote:Great explanation David.

I have an off the topic question. I am trying to apply rules on CR and think through but haven't been able to see significant improvement. Is there something that you would suggest to improve my CR?

CR is much less about formal rules than it is about a kind of logical tenacity. (No rule is going to be terribly helpful if you don't fundamentally understand the argument.)

My advice: for the time being, do CR questions very slowly and very thoroughly. Never pick an answer because it sounds good at first. Always have a line of logic in your head to justify your selection. For example: (C MUST be the answer because the goal is to increase profit and this scenario would lead to a decrease in expenses with no change in revenue. Then break down each answer choice. (This one is irrelevant. This one does the opposite of what I want it to, etc.) Wash/rinse/repeat

In time, you'll begin to see the same kind of patterns showing up in incorrect answers. What you're really doing is training yourself to be logically rigorous.

Thanks David. Appreciate your inputs.