<p>I wasn’t suggesting that cutoff scores are not adjusted. They are, of course, but not for reasons having anything to do with percentiles. Nothing in the CB material quoted above suggests that there are percentile targets and, most importantly, the standardization of the test could not be maintained if there <em>were</em> such targets.</p>
<p>The cutoff scores are generally adjusted to account for variations in test difficulty (as determined by the equating questions + readers etc.). In the unusual, somewhat controversial, but arguably necessary rescaling of the AP biology test in 2007/2008, the CB determined that the scores were not appropriately matched to college level abilities (the primary design goal of the AP scoring is that, for example, a “4” should be equivalent to a “B” in the appropriate college course). See [thread=542421]this thread[/thread] and the last post in particular for interesting details about the bio situation. The CB would not have reasoned that the percentage of students getting 1s needs to be 33% or so; they determined that a “2” on the 2007 was more like an “F” than a “D”.</p>