We are told that there is a great deal of geographical variation in the frequency of many surgical procedures. Now we need to support the conclusion that much of that variation is due to unnecessary surgical procedure.

So we are given some facts and a conclusion, and we need to select the statement that, if established, would make our argument the strongest. In other words, we are trying to complete the argument with information that would most support the conclusion.

Let's review what we have so far:

• "There is a great deal of geographical variation in the frequency of many surgical procedures."
• What does that variation look like? Well, there is "up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies." So the frequency of those procedures varies geographically.
• What causes that variation? Several theories could explain this geographical variation, but we are given one specific theory: "much of the variation is due to unnecessary surgical procedure."

But we don't have any evidence that this theory is correct. We need something that would help support this theory.


(A) is tempting because this could lead to evidence that would support our conclusion. But whether (A) hurts or helps our argument depends on what those local review boards actually find. Perhaps they'll find that, in the areas with high numbers of surgical procedures, many of the procedures were actually unnecessary. That would obviously strengthen our conclusion.

But we can't assume that the boards' results will help our argument. Perhaps the data from the review boards will actually contradict our conclusion. Or perhaps the review boards themselves will have local biases (i.e. different opinions about what constitutes a "necessary" surgery).

Choice (A) MIGHT lead to results that strengthen our conclusion. But, without further information, we can't be sure. We can hang on to this one for now, but (A) is not looking great.


This one's much better. If the variation is actually due to factors that influence the INCIDENCE of diseases that might require surgery, then we would have an explanation that contradicts our conclusion. For example, perhaps people living along the coast are, for some reason, more susceptible to tonsillitis and thus are more likely to require tonsillectomies. This would indeed explain a geographical variation in tonsillectomies and would weaken our conclusion.

If choice (B) is established, then we can eliminate this alternate explanation. That would directly strengthen our argument, so (B) looks good.


Simply knowing that different types of procedures are often performed unnecessarily does not support our conclusion. Do unnecessary surgical procedures explain the geographical variations described in the passage? Choice (C) doesn't support this theory, so eliminate (C).


This statement suggests that it is difficult to distinguish between necessary and unnecessary procedures. This, in turn, suggests that it would be difficult to actually test our theory. If we can't confidently determine that some surgeries were unnecessary, how can we show that unnecessary surgeries explain the geographical variations?

Choice (D) suggests that our theory might be difficult to study, and it certainly does not support our conclusion. Eliminate (D).


Say we have an area that performed ten times as many hysterectomies, prostatectomies, and tonsillectomies as another area. According to our theory, many of the surgeries in the first area were probably unnecessary. This would explain the variation. If we can show that many of the surgeries in the first area were in fact unnecessary, then our theory would look pretty good.

That would NOT necessarily mean that, in general, unnecessary surgical procedures are performed about as frequently as unnecessary hysterectomies, prostatectomies, and tonsillectomies. Maybe, for some reason, unnecessary hysterectomies, prostatectomies, and tonsillectomies are performed much more often than other unnecessary surgeries.

If we can show that hysterectomies, prostatectomies, and tonsillectomies were performed unnecessarily in areas with high frequencies of such operations, then we've demonstrated that our theory is valid. It doesn't matter whether these trends apply to surgical procedures in general. Eliminate (E).

(B) is the best answer.
_________________

1) There is a great deal of geographical variation in the frequency of many surgical procedures

2) Up to tenfold variation per hundred thousand people between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.

Conclusion: Variation is due to unnecessary surgical procedures

A: A local board of review at each hospital examines the records of every operation to detemine whether the surgical procedure was neccesary.
- Does not tells us that redundant surgical procedures cause variations

B: The variation is unrelated to factors(other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered.
- Explains that variation is due to the surgical procedures alone and nothing else

C: There are several categories of surgical procedure(other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unneccesarily.
- Does not explain the conclusion

D: For certain surgical procedures, it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have succeeded.
- Not useful

E: With respect to how often they are performed unneccesarily, hysterectomies, prostatectomies, and tonsillectomies are representative of surgical procedures in general.
- Not useful

B is best.

The OA is B.

Here is the official explanation:

To establish that much of the varation is due to unnecessary surgical procedures, it is necessary to eliminate that possibility that the geographical varation reflects varation in the incidence of disease treated with these procedures. Choice B, if established, would eliminate this possibility and is thus the best answer.

Review boards (choice A) would provide some control against unnecessary procedures, so choice A would, if anything, tell again the suggested conclusion. Neither choice C nor choice E bears on the conclusion, since neither the conclusion nor the cited geographical variation involves procedures are of the kind choice D describes, the diffculty of determining an individual operation's necessity would merely increase the difficulty of verifying the suggested conclusion.

For me, B is clear and typical for GMAT:

[Cause: surgical procedures] --?-> [result: variation]
We need: there is no other cause (but surgical procedures) that results in [variation]

At the same time, C is also a typical trap: it says something about other surgical procedures (out of scope), but we consider here the variation in the numbers of hysterectomies, prostatectomies, and tonsillectomies.
_________________

No, this is not an assumption question.

The question asks us to identify the option which will best allow us to determine whether much of the variation in surgical procedures across geographies is due to unnecessary surgical procedures.

A: Incorrect. Even if a local board reviews for the necessity of surgical procedures, we have nothing here to tell us whether they end up recommending unnecessary surgical procedures
B: CORRECT. If the variation is unrelated to factors related to the incidence of diseases, then it must be a result of incorrect recommendations being made
C: Incorrect. Even if a large number of surgical procedures are incorrectly recommended, we do not have enough information to conclude that the variation is a result of these
D: Incorrect. If it is difficult to determine whether the procedures were necessary, it will be more, and not less difficult to determine the need for them
E: Incorrect. Similar to C.

(B) is therefore correct.
_________________

Like Word problems in algebra, it is very important to assimilate the questions in CR and then simplify them in common terms

THE QUESTION IS
There is a great deal of geographical variation in the frequency of many surgical procedures - up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.

To support a conclusion that much of the variation is due to unnecessary surgical procedure, it would be most important to establish which of the following ?

A)A local board of review to each hospital examines the records of every operation to determine whether the surgical procedure was necessary.
B)The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered.
C)There are several categories of surgical procedure (other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unnecessarily.
D)For certain surgical procedures, it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have succeeded.
E)With respect to how often they are performed unnecessarily, hysterectomies, prostatectomies, and tonsillectomies are representative of surgical procedures in general.

The question is making us to pick the assumption, which is noting but an understated premise. SO we have to pick an answer that is the assumption made to derive the conclusion. This argument can be simplified and broken into premises and conclusion as follows :-

Premise 1 ) There is a huge variation in number and type of surgeries in a country. Location A has 300 eye surgeries, Location B has 200 heart surgeries and Location C has 400 kidney surgeries.
Premise 2) ----- NOT GIVEN------
NO OTHER PREMISE IS GIVEN. WE ARE DIRECTLY GIVEN A CONCLUSION AND ASKED TO PICKED THE MISSING PREMISE 2

CONSLUSION ) These surgeries were unnecessary.

If you look at Premise 1 only, you might conclude that many people in location A are suffering from eye disease. Population of Location B suffers from a heart disease, and Location C has some disease that is affecting the kidneys of many people. That is the reason there is no much variation in each location and its disease type. These diseases must be dangerous if not treated urgently.

But then comes the conclusion that say :- THE SURGERIES WERE UNNECESSARY.
Now, If we add a premise such as :- This variation is not caused due to the difference in number of people suffering from eye, heart and kidney disease.

How does our argument now looks like ?? ==>
Premise 1 ) There is a huge variation in number and type of surgeries in a different parts of the country.
Premise 2) This variation in surgeries is NOT because different people suffer from different disease in different location.
Conclusion) If these variations are not because people were suffering==> then these surgeries were unnecessary.
_________________

The below explanation is from David (Veritas Prep) -

This is a special type of the strengthen question where the conclusion is in the question stem. Please be on the lookout for this as it occurs fairly regularly.

The conclusion is "much of the variation is due to unnecessary surgical procedures" This indicates a cause and effect relationship. We are, in effect, saying that the reason that there is a geographical variation in the listed procedures is because in the areas where more procedures are performed many of those procedures are not necessary.

Now there could be other reasons for a variation in the number of surgeries. For example, the new natural gas wells that are being drilled in people's back yards have been proven to contaminate the water supply and so it would be very reasonable to see additional cases of cancer and therefore additional procedures near these poisonous wells. So that would be another cause not unnecessary procedures, but variations in the toxicity of various places around the U.S. (or the world depending on how you read the question).

In order to strengthen a question that involves cause and effect, you will want to consider the possibility of blocking an alternate cause. In this case we are saying the cause is the "unnecessary procedures" so we want to block the things that would make these procedures necessary - like variations in the age of the population, the health of the people, the quality of the water, even the ability of the people to pay for the procedures.

Answer Choice B does this. It says, "The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered." So this blocks the idea that the cause of varying rates of procedures would be any of the factors (age, health, toxins) etc. mentioned above. So we strengthen one cause by blocking another.

GMATNinja ,RonPurewal , sayantanc2k ,mikemcgarry ,daagh ,egmat ,EMPOWERgmatRichC ,
ChiranjeevSingh , AjiteshArun
other experts -- can you please help with a detailed explaination to eliminate other options!!
_________________

The stimulus says there is a great deal of geographical variation in the frequency of many surgical procedures. The many is important here. The stimulus is not saying that there is variation in the frequency of every possible procedure—just in "many". Then the stimulus tells us which procedures form the "many" (hysterectomies, prostatectomies, and tonsillectomies). If you're not sure about this, read the stimulus as "there is a lot of variation in the frequency of many surgical procedures—up to tenfold variation in A, B, and C procedures". The part after the dash limits the scope of the question. This is different from trying to change the "degree" with something like "there is a lot of variation in the frequency of many surgical procedures—and up to tenfold variation in A, B, and C procedures".

The conclusion is that this variation can be explained by unnecessary surgical procedures. We need to strengthen this, so the correct option will help us believe that unnecessary hysterectomies, prostatectomies, and tonsillectomies are being performed in some areas (more frequently than in others).

This option says that there is (already) a local board of review at every single hospital. If such a board reviews surgical procedures to check whether they were necessary or not, we are LESS likely to believe that the variation is due to unnecessary surgical procedures.

Keep in mind that this option is not presenting us a recommendation. It tells us that such boards are already in place. Also, don't add any extra information (like "the boards are not functioning well").

This is good. The conclusion is that the variation is due to X. This option strengthens that conclusion by saying that the variation is unrelated to factors other than X (leaving only X to explain the variation).

This option (a) discusses procedures other than the ones the question is concerned with and (b) gives us no information about the link to geographical variation. If it had said that the same geographical variation is observed in other categories, we would have had some reason to think that the variation observed in the frequency of hysterectomies, prostatectomies, and tonsillectomies is due to unnecessary surgical procedures. But this option doesn't do that. It just says that there are other procedures that are often performed unnecessarily.

If this is true, all geographical regions should find the process equally difficult. There's nothing here to suggest that there is any geographical variation in the frequency of unnecessary surgical procedures. Also, this option doesn't really specify whether "certain" includes hysterectomies, prostatectomies, and tonsillectomies.

Whether the three are representative or not is irrelevant. We first need to establish that the variation in the frequency of the three procedures is in fact due to unnecessary surgical procedures.
_________________

There is a great deal of geographical variation in the frequency of many surgical procedures—up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.

To support a conclusion that much of the variation is due to unnecessary surgical procedure, it would be most important to establish which of the following?

(A) A local board of review to each hospital examines the records of every operation to determine whether the surgical procedure was necessary. --It weakens the argument

(B) The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered. --Correct. It removes the possibility that any other factor might impact the procedure

(C) There are several categories of surgical procedure (other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unnecessarily. --Out of scope

(D) For certain surgical procedures, it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have succeeded. --This weakens the argument

(E) With respect to how often they are performed unnecessarily, hysterectomies, prostatectomies, and tonsillectomies are representative of surgical procedures in general. --Out of scope

Author is looking for an evidence to support “variation”. B is the best answer to explain variation, because variation is not considered while making surgical decisions. It is easy to understand that when surgeons do not try to Avoid variation (there is no valid reason to do so), variations occur. Moreover, I assume variation is considered extra procedure or unnecessary procedure. The goal of surgeon is to operate successfully, so extra steps is not a problem.

Posted from my mobile device

Please correct me if I'm wrong.

Premise: 1) The variance in surgical procedures is tenfold variation in different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.

Conclusion: the variance is due to the unnecessary procedures.

To Strengthen

Pre thinking: there are no other factors in the variance.

A: I think it looks like evaluation so out.
B : It related to Pre thinking.
C : At first, I think this choice strenthen the conclusion but the categories is unrelated.
D : How difficult is not related the variance so out.
E : No related with Conclusion so out.


Hope it correct.

I faltered in this one - may be because of the overall structure of passage - and fell for trap answer C. Here's my post attempt analysis.

There is a great deal of geographical variation in the frequency of many surgical procedures—up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies. - Here's a fact laid down in the passage by the author that there is geographical variation in the frequency of many surgical procedures(SP). 'up to' suggests the maximum variation possible between different areas for H, P and T. It can be considered as example given in support of the fact that there is vast amount of variation.

To support a conclusion that much of the variation is due to unnecessary surgical procedure, it would be most important to establish which of the following? - 'To support' suggests that we need to strengthen the argument/conclusion. Conclusion is that much of the variation is due to unnecessary surgical procedure(USP). So, in order to do so, what must be done?

Till this point, we understood that we need to EITHER disapprove/weaken any fact that says that the variation is because of surgical procedures OR support one which suggests that variation is due to some other unsought USP. However, latter is far better for our case.

(A) A local board of review to each hospital examines the records of every operation to determine whether the surgical procedure was necessary. - This goes in either of the directions as we are more interested in the result the review would get us. Was it necessary or was it not?

(B) The variation is unrelated to factors (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered. - The phrasing is little confusing. All it says that unrelated factors to SPs caused the variation as they(unrelated factors) let to surgeries. Some local factors related to geography led to some disease and thus surgeries.

(C) There are several categories of surgical procedure (other than hysterectomies, prostatectomies, and tonsillectomies) that are often performed unnecessarily. - The word 'several' if replaced by 'some' then probably it becomes clear that this is not the right answer. Also, SPs other than H, P and T, if performed unnecessarily, would suggests that variation was indeed because of SPs and not USPs. H, P and T variation is given as an example - an extreme one - and suggests that there are other SPs which might be necessary. What if we have another extreme case where the variation is minimal geographically and most of the cases have such minimal variation? OR What if H, P and T is an exception among the cases? The passage actually doesn't touches upon this aspect. The point is this is an open choice like A, which leads us to nowhere.

(D) For certain surgical procedures, it is difficult to determine after the operation whether the procedures were necessary or whether alternative treatment would have succeeded. - Again, generically speaking, we are not concerned of certain SPs. Are those 'certain SPs' number most OR least OR exception. Basically this is irrelevant.

(E) With respect to how often they are performed unnecessarily, hysterectomies, prostatectomies, and tonsillectomies are representative of surgical procedures in general. - The word 'how' jumps in and we are not concerned how H, P and T are performed unnecessarily. Again Irrelevant.

I don't know if this analysis is good or bad but this is how i understood it.

Answer B.
_________________