It's a well-known fact that the average intelligence of university students has been declining over the past four or five decades. This is true in spite of the fact that the average university grades have been going up.
The decline in average intelligence is exactly what one would expect, as Razib Khan explains on his blog Gene Expression: College students are not as intelligent.1
Surprisingly, the typical student at my university doesn't want to hear this. You'd be impressed by the number of explanations they can come up with to refute the data. Maybe we'll see some of them in the comments. Are they scientific explanations?
You might also be surprised at the reluctance to accept the fact of grade inflation. The most common explanation for grade inflation is that today's students are smarter than those of the 60s and 70s and that's why they get higher grades.
1. This is not an argument against increasing the participation rate and expanding university enrolment. I'm in favor of that. Let's just realize that there are consequences that universities need to deal with.
The real question we need to address is gradation rate. In an ideal world, what percentage of those who enter university should graduate? Should it be 100%? 50%?