<p>The College Board conducts validation studies on all AP tests from time to time by giving the tests to actual college students who have just taken a matching college course. That’s what sets the scoring levels for an AP score of 5, 4, 3, and so on. Different colleges have different levels of course difficulty, which is also why you can place out of a college course with an AP score at some colleges but not at all, even with a 5, at other colleges.</p>