[Verginius Rufus]

I think grade inflation began about the time colleges started having student evaluations of professors. Professors who graded hard got lower evaluations from students. If you were not tenured then your job might be at risk for having low scores on the evaluations. I think this became widespread about the end of the 1960s.

[Myrddin]

At UCSD the students developed evaluations of professors independent of the school administration. It was aimed at identifying good instructors from flagellating butt heads that waste your time and money. A good free market approach. The bad profs were weeded out by having insufficient numbers of students to justify the specific class meeting.