Often patients with ankle fractures that are stable, and thus do not require surgery, are given follow-up x-rays because their orthopedists are concerned about possibly having misjudged the stability of the fracture. When a number of follow-up x-rays were reviewed, however, all the fractures that had initially been judged stable were found to have healed correctly. Therefore, it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable.
Which of the following, if true, most strengthens the argument?
45. Often patients with ankie fractures that are stable, and thus do not require surgery, are given follow-up x-rays
because their orthopedists are concerned about possibly having misjudged the stability of the fracture. When a
number of follow-up x-rays were reviewed, however, all the fractures that had initially been judged stable were
found to have healed correctly. Therefore, it is a waste of money to order follow-up x-rays of ankle fractures
initially judged stable.
Which of the following, if true, most strengthens the argument?
(A) Doctors who are general practitioners rather than orthopedists are less likely than orthopedists to judge
the stability of an ankle fracture correctly.
(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.
(C) X-rays of patients of many different orthopedists working in several hospitals were reviewed.
(D) The healing of ankle fractures that have been surgically repaired is always checked by means of a
follow-up x-ray.
(E) Orthopedists routinely order follow-up x-rays for fractures of bones other than ankle bones.
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, iftrue, 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.
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.
C 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.
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.
The correct answer is C