Agreed. However I think the early coaching and later coaching is changing the nature of these tests. Here is the experiment. Take 100 kids from some good public school who can confirm they have not been coached for the PSAT other than being familiar with the rules etc. give them 1985s PSAT or perhaps 1992 (assuming you can identify the last year that before coaching became common later is better because of changes in teaching and cultural references) and grade them based on 1985s scale. I bet they will do better percentile wise than they would on 2015s PSAT. As opposed to kids who have been coached who will do the same on both. Yes I do know that scores from 1995 or 2005 I forget went up because they changed the sat. Since the PSAT is a curved test, how you do does depend on who else is taking it. Maybe not over a single administration but certainly over time. So if people are being coached and do better that changes the result for everyone, so the very bright kid who would have done great in 1990 now has to study because everyone is coached.