There is a great deal of geographical variation in the frequency of ma

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.