<p>CB says they don’t compare the test takers’ results. But how would they determine the difficulty without looking at the results of different test takers?
Would this mean that taking the test with lower-scoring people get you a better curve?</p>
<p>The CB compares the test takers’ performance on the unscored equating sections in order to determine test difficulty (by separating the quality of the test takers from the difficulty of the test). The equating sections contain questions identical to those on equating sections on an earlier test. By “results”, the CB means test takers’ performance on the scored portion of the test.</p>
<p>The answer to your second question is, briefly: no.</p>
<p>Your percentile ranking for any given SAT test is determined by comparing your scores to the test takers who took the test in the prior test year (Oct through June). Thus, your percentile ranking for the March 2013 test will be determined by comparing your scores with those who took the test between Oct 2011 and June 2012.</p>