Until 1990, the results of the Reading Level Assessment Test (RLAT) given in middle schools of Brooklyn and Queens indicated that the reading ability of students in the two boroughs was nearly identical. Since 1990, however, the average score on the test has been markedly higher in Brooklyn than in Queens. The Superintendent of the Brooklyn schools believes that his students did better on the test because all Brooklyn middle schools reinstated minimum reading level requirements. Under these requirements, all students in Brooklyn reading below grade level are required to attend after-school reading workshops once a week.
If the statements above are true, which one of the following MUST also be true?
A. The average score on the RLAT in Brooklyn has increased the minimum reading level requirement.
(A) is incorrect because it states the inverse of the argument, essentially saying that the effect leads to the cause, which is not logical. The argument is that the reinstatement of the minimum reading level requirement (i.e., higher standards) in Brooklyn led to higher RLAT scores in that borough. Generally, where a result is attributable to a specific cause, it does not follow that the cause is attributable to the result. A causes B; B does not cause A.
B. There was a minimum reading level requirement in the Queens middle schools at some point before 1990.
(B) is incorrect because there is not enough information in the stimulus by which we could make any firm statements about what was happening in Queens, either before or after 1990. It is important to remember that the argument, attributing the rise in test scores in Brooklyn to higher standards in Brooklyn, is something the Brooklyn Superintendent believes. If he is wrong, and the result is attributable to something else, then the other facts in the stimulus tell us nothing about what's been happening in Queens. Even if he is right, this would not be a logical inference; the standards were reinstated in Brooklyn, which means they existed at one point and then were eliminated before being put back into place, but we don't know whether they ever existed in Queens. The fact that the Queens scores tracked the Brooklyn scores before Brooklyn reinstated the standards suggests they probably didn't, but again, we don't know enough to say for sure.
C. There was no minimum reading level requirement in the Brooklyn middle schools at some point before 1990.
(C) is correct. The Brooklyn Superintendent believes that test scores have risen since 1990 because the minimum reading level requirements were reinstated. That means they were in place at some point, then were eliminated at some later point before being put back into place. If the scores have risen since 1990, and the Superintendent attributes that rise to the reinstatement of the standards, then it must be true that at some point before 1990, there were no such standards in place. Otherwise the rise in scores since 1990 cannot reasonably be attributed to the reinstatement of the standards.
D. There was no minimum reading level requirement in the Queens middle schools at some point after 1990.
(D) is incorrect for the same reason as (B). Because the stimulus characterizes the argument as something the Brooklyn Superintendent believes, the possibility that he is wrong eliminates choice (D) as a logical inference. It could be true, but it doesn't have to be true. Again, if the Superintendent is wrong, if the rise in scores is actually attributable to something other than the reinstatement of the standards, then the remaining facts in the stimulus allow no inferences to be drawn about anything happening in Queens. Had the stimulus made the argument directly, then this might have been a logical inference. If the Superintendent is right, then this is probably true. But it didn't, and we don't know.
E. Since 1990, the RLAT score of every student in Brooklyn has been higher than the RLAT score of every student in Queens.
(E) is incorrect because it's ridiculous. Just because the average score of one group is higher than the other doesn't mean that every member of the first group scored higher than every member of the second. You can receive a higher grade than another student on one notebook check and still end up with a lower overall average than that person.