It’s interesting that the real change in grading appears to have occurred in the period between 1962 and 1974, probably coinciding with the increase in conscription for the Vietnam War. After 1974 things appear to trend toward a return to baseline. Then in 1990, something new happens that drives grade inflation.
I think it’s pretty obvious what happened: increased competition for graduate school slots put (and still puts) pressure on faculty to not give C’s and to give more A’s.
I don’t mean that faculty received orders telling them to stop giving C’s and start giving more A’s. But admissions to decent post-graduate programs is so competitive that a B has a noticeable effect (lowers the GPA) and a C is the new F. Combined with students attempting to game the system to aid their GPA’s (i.e., take ‘gut courses’), and you’ll get grade inflation.
But this model grade inflation requires that admissions to good programs becomes more difficult. Is it? If we look at MD’s, between 1990 and 2005, the number of MD degrees awarded was effectively constant. Meanwhile, during that time, the number of biology degrees essentially doubled, and the total number of college graduates increased 86%.
If we consider MBAs awarded from the top 100 programs, by definition, you can’t have an increase in the top 100 programs, and I haven’t found any data suggesting that there is a massive increase in the number of MBAs awarded by these programs.
So I’ll posit that a major factor in grade inflation is the increased competition for graduate school slots. This has led to B’s and C’s having a much stronger influence on students. At the same time, students have become more willing, when possible, to avoid courses that are graded harder. While it might seem that if everyone is getting high grades, that high grades don’t matter. But if you don’t have a high GPA, then you stand out as a poor student–there is a rachet effect that pushes grades upwards.
If we want to reduce grade inflation, then we have to stop making grades so critical for acceptance into increasingly selective ‘good’ graduate programs. Until then, grade inflation it is. The good news, I suppose, is that grades can’t get any higher…