<p>. . . at least for some. I skimmed the report, linked by fignewton. The “correct” operation of the equating procedure (to ensure that the same level of performance yields the same score, on different test dates) is based on the assumption: For the students testing on a given date, the performance on the equating section is accurately representative on their “true” performance on the test as a whole.</p>
<p>We know that the equating sections must contain questions that have been used multiple times. This will tend to create some level of familiarity with these questions in the test-prep industry. Therefore, I’d hypothesize that students who have been extensively prepped might actually perform better on these questions than they do on the test as a whole (since presumably the whole test will contain some questions of a less familiar type). Because of the equating procedure, this will tend to make the testing population look “smarter” than they really are, thus shifting the mean up and giving people a small boost.</p>
<p>So, suppose that you are generally talented at test-taking, but you have not prepped. If my hypothesis is correct, I believe you should aim for dates when the largest numbers of highly prepped students are taking the test. Here’s my thinking: The highly prepped students will perform better relative to you on the equating section, but they will not perform as well on the remainder of the test–by this, I do NOT mean that they will outperform you on the equating section, just that the ratio of their score to yours is likely to be higher on that section than on the rest. Your “underperformance” on the equating section does not matter to your score. Meanwhile, the “overperformance” on the equating section by the prepped students will boost the score on the 200-800 scale that is assigned to the mean, and this will tend to yield a boost for you, wherever you fall on the scale. In addition, the pattern of performance by the prepped students might actually reduce the apparent standard deviation within the testing population, thus giving you an extra boost for scoring near the top.</p>
<p>If CB could obtain accurate data on the level of test-prep for individual testers, they could determine whether or not my hypothesis is correct.</p>