This is purely anecdotal evidence based on casual observation, but I’ve had a number of friends who teach college argue that they’ve seen a sharp downturn in student performance in the last few years, particularly in critical thinking skills. Simple memorization and repetition seems about the same, but students seem to be much less capable of thinking through the logic of problems.
Our suspect is the No Child Left Behind act and the increased emphasis on standardized tests. The timing makes it a plausible causal agent, although that’s obviously insufficient in itself. But I can verify that test grades on short answer questions in my American Government class have declined in the past few years as the NCLB generation has come to college. And after talking today to a friend who also teaches introductory courses, we realized we have to change our teaching style in response to this, but we don’t know what we need to do.