I used to teach at the University of North Carolina and at a community college. I always reserved the right to “curve” any particular exam, and add a final curve at the end of the semester if necessary.
I took the approach to challenge my students. Of course, they tended to whine a lot (“that test was hard!”). If a particular test had an average of, say, 62, with a class high score of 89, I would probably add 8 points to everyone’s test. Class size, subject, and level were always considered and treated in different ways. The main thing is to be internally consistent within any given class.
Of course, many teachers tend to think the best exam is one where the final spread is 75% of the students above an 85. To me, this test is not challenging enough to separate who really knew the material vs. who lucked out on an easy test.
At the end of the semester I would analyze the final averages and look for natural breaks in the distribution. Any additional curve could only work to a student’s advantage. That is, I always used a 10-point scale. At times I would maybe group the 87s-89s in with the As; but I would never ‘scale up’ to make the lowest ‘A’ a 93 or something.
As a student, I had professors use all sorts of curves. A curriculum in the hard sciences tends to lend itself to a whole lot of low scores. One physics professor used a factor based on the class average. Let’s say the exam average was a 57. To scale to 70 you would need a factor of 1.228. Then, everyone’s score got multiplied by 1.228. So, if you originally got a 95, you would end up with a 116.7! Of course, if you got a 30, you ended up with a 36.8. Rationale being, why would someone who blew off the test deserve the same points added his score than someone who truly achieved. A case of the rich getting richer.
And all this is aside from grade inflation. Any lower level class where 75 get As and Bs is, IMO, too easy. It is different when it comes to upper level classes and graduate school. Anyone who gets to the upper levels of one’s specialty should be proficient enough to get at least a ‘B’ in most cases. Introductory classes do no favors for anyone if the right people aren’t weeded out. Hey, how else do you know that med school isn’t for you if you cruise through Zoology 1001 without really learning anything?
Boy, I’ve rattled on and still haven’t begun to scratch the surface on the grading situation in higher education. I have lots to say on this subject.