Often patients with ankle fractures that are stable, and thus do not

No this is not what it is saying.

The author is taking data and drawing a specific conclusion from it. Whenever you see a survey, sample, poll, etc. You should always be suspect of whether the data is representative of the whole.

For instance, if you read about polls for presidentail elections back in the 1920's the polls would indicate that a certain president would win by an overwhelming majority. However, the polls were conducted via telephone and only wealthy citizens had a telephone and the conclusion reached by the poll was not representative of the total population. Hence the prediction was wrong.

In the case of this argument, the author points to a sample of Xrays that were done a second time and the injury was always healed. What if this sample is only from the Worlds Greatest Orthopedist? Would the data gathered from this Orthopedist be representative of all Orthopedists? No. This would make it impossible for anyone to make a conclusion that 2nd xrays should never be done.

So by saying that the data is gathered from "many different orthopedists working in several hospitals", you are confirming that the data is representative and therefore strengthening the argument by eliminating the possibilty that the data is representative of only the Worlds Greatest Orthopedist.

Why is it B? The conclusion states that, "it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable." The conclusion states that the ankle is already fractured, which means that answer B is out of scope as its subject is about "many ankle injuries" in a broad sense (and not just to those pertaining to ankle fractures).

I think the answer is C because the conclusion is based upon a review of "a number of follow-up x-rays." I think the question pertains to the issue of sample size and accuracy. If (as it is with answer choice C), the sample was drawn from several sources, then the findings from the sample size become less biased and more robust which would then strengthen the conclusion.

C says -
C. X-rays of patients of many different orthopedists working in several hospitals were reviewed.

Does it means that X rays from orthopedists suspected whether its true or false and hence gone for review????

Like most GMAT verbal questions, the difficulty is not in the passage but in the answer choices. GMAT verbal does intentionally make the answer choices unncessarily verbose and confusing. GMAT should test the logical reasoning of test takers, not the ability to clear confusion in a bad written English sentence. Unfortunately, this is the way GMAT operates and it is unfair to non-native English speakers.

In CR, it's very important that you can distinguish between the premises and the conclusion. Then it's much simpler to answer the question.

I actually picked B before looking at all the responses and answers. The conclusion of the passage is: "It's a waste of money to order follow-up x-ray of ankle fractures intially judged stable." The premise that strengthens the conclusion above would provide fact/information that further prove that taking x-ray is unecessary and wasteful. Of all answer choices, B shows that many x-rays ordered for ankle injuries do not show fracture of the ankle. Thus, it makes follow-up x-rays unnecessary & wasteful.

Wonder if that makes sense?

I have chosen the answer C for this question:

A. We are not really concerned about general practitioners in this case, so this is irrelevant. Also, if doctors are generally less likely to judge the stability of an ankle fracture correctly, this would be a reason to actually keep doing x-rays - this statement would actually weaken the argument.

B. We are concerned about the "follow-up x-rays" once a fracture has been determined. This answer choice states that "initial x-rays" are ordered for ankle injuries. Although this may seem like a good answer, the situations are not quite the same. Therefore, this is irrelevant information.

C. At first glance, I wasn't sure that this answer was correct. However, I looked at the statement "When a number of follow up x-rays were reviewed..." and determined that in order to strengthen the argument, you might want to close the "weakening" gap. A way to weaken this argument might be to say that all the reviewed x-rays were done by a single orthopedist. In order strengthen this argument, we would counter by saying that we have a very representative sample of patients who were reviewed by many different orthopedists.

D. We are not concerned with ankle fractures that have been surgically repaired (unstable fractures).

E. We only care about ankle fractures in this argument, not about x-rays for fractures in other bones.

GENERAL METHOD:

In CR, Strengthen and Assumption are always considered the most difficult questions. To solve Strengthen question, we should:
- Identify the conclusion - This is what you're trying to strengthen. MOST important.
- Personalize the argument if you can.
- Look for weaknesses in the argument - It seems contradict, but in real GMAT, the answers are always used to eliminate that weakness. Frankly, that's the logic GMAC uses

Avoid Shell game that always support a conclusion that is similar to, but slightly different from the one in the question.

APPLY:

Premise: Often patients with ankle fractures that are stable, --> do not require surgery, are given follow-up x-rays
Premise: When follow-up x-rays were reviewed, however, all the fractures that had initially been judged stable were found to have healed correctly
Conclusion: it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable

What is the weakness: Do the follow-up x-rays that were reviewed by the doctors represent for all follow-up x-rays in general - KEY Point.
Best answer will eliminate that weakness.

CONSIDER EACH ANSWERS:

A. Doctors who are general practitioners rather than orthopedists are less likely than orthopedists to judge the stability of an ankle fracture correctly. - WRONG - Out of scope.

B. Many ankle injuries for which an initial x-ray is ordered are revealed by the x-ray not to involve any fracture of the ankle. - WRONG - SHELL GAME - Please re-read the conclusion, "it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable". The conclusion is only about the ankle fracture initially judged stable, not all ankle injuries in general. On the other hand, B is TOO GENERAL, It does NOT support a conclusion we need to strengthen.

C. X-rays of patients of many different orthopedists working in several hospitals were reviewed. - CORRECT - Eliminate the weakness perfectly.

D. The healing of ankle fractures that have been surgically repaired is always checked by means of a follow-up x-ray. - WRONG - Out of scope

E. Orthopedists routinely order follow-up x-rays for fractures of bone other than ankle bones. - WRONG - Out of scope.

I hope it could help.

_____________________________
Please kudo if my post helps. Thank you

Hi GMATNinja generis GMATNinjaTwo

How do we perform PoE for B and C when RESULTS or outcomes are NOT known?

This is a strengthen the argument question.

Like weaken, strengthen questions also require us to isolate the conclusion. As we will be looking for the answer that makes our belief stronger on the premise-conclusion relationship such as analogies, survey, reports, statistical data etc.

Also, protect the missing information
a) by keeping any option that fills the gap
b) by eliminating the answer that attacks the missing information

Expert suggestions: How do we know if what these experts or analysts think, matters? Eliminate any option that has the expert’s opinion.

Similarly, either introducing other examples doesn’t strengthen or introducing exceptions doesn’t weaken since in both the cases, there is just no way to automatically know that those other cases carry a sufficient resemblance to who or what the argument is about.

Eliminate any answer that instead of strengthening the argument, weakens it.

Causality and Strengthen Questions: The steps taken to prove a cause-effect relationship is strong requires the OPPOSITE steps as weakening:
o Prove that when the cause occurs, effect always takes place
o Prove that when effect occurs, it occurs because of the cause.
o Eliminate any other reasons that cause the effect.
o Prove that the relationship between C -> E cannot be reversed.
o Prove that statistical improbability won't occur.


Conclusion: Therefore, it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable.
Assumption: The data that was used to review was from a good source and shows the correct representation.
A) Out of scope.
B) This option also doesn’t reinforce the idea that it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable.
C) This option tells us that the data in review was not biased. Keep this option.
D) This provides an alternate reason why the x-ray may be required.
E) Other than ankle bone is out of the scope of this argument.
C certainly helps and is the answer.


Kudos if my answer helps!

GMATNinja
hello sir

if option E read as "orthopedists routinely order follow-up X-rays for fractures of ankle bone."
would the option strengthen the conclusion that"it is a waste of money to order follow-up X-rays of ankle fractures initially judges stable."?

Even with that change, (E) wouldn't do much to strengthen the conclusion. We already know from the passage that, "Often patients with ankle fractures that are stable... are given follow-up x-rays." So your version of (E) wouldn't really give us any new information.

But don't torture yourself trying to come up with your own versions of the answer choices. As long as you understand why (E), as written, is incorrect, you're in great shape!

Official Answer

Argument Evaluation

Situation Often patients with ankle fractures that their orthopedists have judged not to require surgery are given follow-up x-rays to check whether the fracture healed correctly. An examination of a sample of those x-rays found that the ankle had, in each case, healed properly.

Reasoning The question is which of the options, if true, would most strengthen the argument. The argument is based on data concerning follow-up x-rays, each of which revealed no problem with the orthopedist's initial judgment that the ankle fracture was stable (and would heal without surgery). This invites the question whether the follow-up x-rays are really needed. The argument concludes that they are a waste of money. But was the x-ray data truly representative of orthopedists generally? After all, some orthopedists—perhaps more experienced, better-trained, or employed at a facility with better staff or facilities—may be much better than others at judging ankle fractures. If we add the information that the data for the conclusion comes from many orthopedists working at many different hospitals, we have greater assurance that the x-ray data is representative, and the argument will be made much stronger.

Option C is Correct. This shows that the sample of x-ray data examined was probably sufficiently representative of cases of ankle fracture judged to be stable by orthopedists.

Why are answer options A, B, D & E wrong? :-

A - Neither the study nor the conclusion that is drawn from it concerns general practitioners, so this point is irrelevant.

B - Naturally many ankle injuries do not involve fractures—x-rays may sometimes be used to determine this—but the argument concerns only cases where there have been ankle fractures.

D - The argument does not concern cases of ankle fracture that have been surgically repaired.

E - The argument concerns only x-rays of ankles. From the information given here, we cannot infer that orthopedists are generally wasteful in routinely ordering follow-up x-rays.

Conclusion:
- it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable.
In other words, when a fracture is initially judged stable, it is stable. No need to get a follow up x ray. The orthos do a good enough job when they review the fracture as stable initially.

So we need to strengthen our conclusion.

(A) Doctors who are general practitioners rather than orthopedists are less likely than orthopedists to judge the stability of an ankle fracture correctly.
This does not strengthen our conclusion. We don't know whether sometimes general practitioners judge the initial stability of fractures but if they do, actually we do need to have a follow up x ray (since they may not do as good a job as orthos)

(B) Many ankle injuries for which an initial x-ray is ordered are revealed by the x-ray not to involve any fracture of the ankle.
Irrelevant. This talks about injuries which are not fractures. We are only concerned about ankle fractures which are initially judged stable. Rest of the injury universe is irrelevant to us.

(C) X-rays of patients of many different orthopedists working in several hospitals were reviewed.
This is interesting. We are concluding that we don't need follow up x rays, that orthos are capable of identifying stable fractures initially itself. If we had reviewed various diff orthos from various diff hospitals, it means that generally, orthos are capable. It strengthens our conclusion. Say if most of the x rays reviewed were of a single ortho, can we say that we don't need to get a second x ray done? What if that particular ortho is capable but others are not? Checking the skills of various orthos helps better establish that a second x ray if not needed. This is the answer

(D) The healing of ankle fractures that have been surgically repaired is always checked by means of a follow-up x-ray.
This is talking about ankle fractures which are not deemed stable initially (since they need surgery). Again, this is outside the scope of our argument. What happens with unstable ankle fractures we don't care. The only relevant topic is "ankle fractures which are initially judged stable".

(E) Orthopedists routinely order follow-up x-rays for fractures of bone other than ankle bones.
Again, as we said before, rest of the injury universe is irrelevant to us.

Answer (C)

I actually ruled C out of scope, so I had to review the OG and my CR Bible notes to understand why this was in fact correct.

Conclusion: It is a waste of money to order follow-up x-rays of ankle fractures initially judged stable
Why?
P1: Follow-up x-rays are given out of concern of patient's doctors (Sentence 1)
P2: A number of x-rays were reviewed, revealing that all the fractures that had initially been judged stable were found to have healed correctly (Sentence 2).

How do you strengthen an Argument? [straight from my flash card summaries of CR bible]
A. Identify and analyse the conclusion – this is what you need to strengthen
- Ask “would this answer choice assist the author in some way”
B. Find missing link between premise and conclusion – these can be assumptions made by the author
C. Look for weaknesses in the argument – because by eliminating this weakness we strengthen the answer.
D. If an argument relies upon surveys/ analogies – then find an answer choice that strengthens the analogy or survey, or establishes their soundness;.

Error Analysis
A - GP vs Ortho debate is irrelevant to the conclusion that we need to strengthen
B - I initially thought this was correct by way of POE, but having understood the correct sentence I see that this is incorrect as the conclusion is only concerned with ankle fractures, not ankle injuries
C - "many...were reviewed" - meaning the sample size may in fact be representative of the population, thus allowing us to conclude with greater accuracy
D - Irrelevant to the conclusion. We already know that ankle fractures are checked by means of a follow-up practice. The discussion point is whether we should curtail this practice, so how does D strengthen this judgement that we should reduce follow-ups?
E - Completely irrelevant. This is making a comment on the general practice now, so how does it help us strengthen the conclusion that we should curtail follow-up x-rays?

hello GMATNinja

i have one question about C. C claims X-rays of patients of many different orthopedists working in several hospitals were reviewed.

Yes they were reviewed but what was the result of these reviewes ? maybe it was proved that it is better to do folow up x-rays ? how do we assume that it strengths statement if the result of the reviews could be recommendation of follow up x rays ?

thanks and have a nice weekend

dave

Hi Dave,

Remember that the passage still states the following:


No matter how many reviews took place, the result regarding all the fractures that had initially been judged stable (within this set number of reviews) was that they healed correctly. We know this was the outcome even before we look at choice (C).

But let's be clear about what choice (C) says and what it doesn't say:


Without choice (C), we have "a number of reviews." With (C), we have "a number of reviews of patients from many different orthopedists working in several hospitals."

This new information doesn't strengthen the argument by changing the literal outcome of the x-rays or the injuries. (C) strengthens the argument by providing information that gives us more confidence in the initial set of reviews. And it definitely doesn't add information to contradict what we've already read about the outcomes of these reviews.

I hope this helps!

I pick C because when i read the argument, the first thing that i though of was 'was the survey big enough' which fits in with C.

anyway using POE:
A compares GPs and orthos....no relevance
B talks about injuries without fracture...no relevance
C tells you that the study was extensive and done in a variety of environments, thus strengthening the fact that you can make a generalised conclusion like the one above..
D tells you that followups are done...which doesnt strengthen the argument
E says that orthos do follow ups on other injuries too...this weakens the conclusion if anything...because if they do it for other things, why should they stop for ankles.

The only remaining answer is C

well thats my way of thinking in any case
obviously could be completely off[/quote]

Option C does not specify that ankle injuries are reviewed. It just generalizes that x rays are reviewed. How that could be right answer?
I still dwell with B. Can you please explain, in other words, why B should be eliminated?

Option C does not specify that ankle injuries are reviewed. It just generalizes that x rays are reviewed. How that could be right answer?
I still dwell with B. Can you please explain, in other words, why B should be eliminated?[/quote]

VeritasKarishma My thought process is the same as venkateshraviraj . I can do POE to get to C. however under pressure, I would pick a different answer for the simple fact that C does not specify patients with ankle injuries. I would have expected it to say 'X-rays of patients with ankle fractures of many different orthopedists...' because for all I know it could be x-rays of patients with I dunno, a sprained knee.

Can you please clarify as it would be greatly appreciated.