Critical Reasoning

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.

OA: B

We're trying to answer a question here: what accounts for the geographical variation in the procedure rate? Is it that doctors in some areas are performing more unnecessary procedures than doctors in other areas? Or is there another explanation? Perhaps there's just more legitimate need for procedures in some areas.

Look at answer B.

Imagine that you and I are surgeons. You're a surgeon in Town A, and I'm a surgeon in Town B. I perform way more procedures than you do. If it turns out that the difference in our procedure rates is unrelated to other factors - the citizens in our two towns are the same age, eat similar diets, etc. - then it might be reasonable to conclude that I'm performing more unnecessary procedures than you are. But now imagine that the difference our in procedure rates is related to other factors - the average age of my town is 97 and the average age of your town is 22. Everyone in my town smokes two packs of cigarettes a day, and virtually no one in your town smokes, etc. Now it's less likely that I'm performing unnecessary procedures. Rather, the population of my town is simply much sicker and thus requires more extensive intervention. So this would be important information to know when trying to evaluate the argument.

Hi Dave,
Thanks for the clarification.

Just one quick clarification required on why option A is INCORRECT : I think, it doesn't really help in establishing/evaluating the causal relationship between unnecessary surgical procedure and much of the geographical variation. In fact, it fails to establish that unnecessary surgical procedure CAUSES much of the geographical variation.

Please let me know whether my analysis is correct ?

RBBmba@2014 wrote:Hi Dave,
Thanks for the clarification.

Just one quick clarification required on why option A is INCORRECT : I think, it doesn't really help in establishing/evaluating the causal relationship between unnecessary surgical procedure and much of the geographical variation. In fact, it fails to establish that unnecessary surgical procedure CAUSES much of the geographical variation.

Please let me know whether my analysis is correct ?

That's correct. (We don't even know what the board of review at each hospital may have found! Did they discover that many procedures were unnecessary or did they arrive at the opposite conclusion? Who knows?)

Please comment on E. I haven't found any good explanation about E.

E. With respect to how often the are performed unnecessarily, hysterectomies, prostatectomies, and tonsillectomies are respective of surgical procedures in general