Slashdot Mirror
Adjusting GPAs: A Statistician's Effort To Tackle Grade Inflation
An anonymous reader writes "A recent analysis of 200 colleges and universities published in the Teachers College Record found 43 percent of all letter grades awarded in 2008 were A's, compared to 16 percent in 1960. And Harvard's student paper recently reported the median grade awarded to undergraduates at the elite school is now an A-. A statistician at Duke tried to make a difference and stirred up a hornet's nest in the process."
Grading on a curve only works for large, introductory courses. The problem is two fold 1) smaller classes cannot be assumed to have a normal distribution and 2) Once you get past intro classes in any subject, there is a strong selection bias so that people in upper level classes all tend to be high level performers in that subject (which also means you can't assume a normal distribution).
The big problem with grades is that they conflate course difficulty and student performance. If you want grades to be a proxy for performance, you have to weight them somehow or other by class difficulty. The problem is nobody can agree on how to rank class difficulty due to academic politics, since nobody wants to be the department that gets the short-end of the stick with class difficulty rankings. In my personal experience, being one of the few people who have taken multiple graduate level classes in 3 disciplines (History, Mathematics and Neuroscience) at that level no field is particularly easier or harder than another, it's just that the type of work one does is very different.
The other issue that I rarely see addressed in all of the 'grade inflation' concern (and which class rank also ignores) is that maybe today's college students are actually working a lot harder than those in 1960 (perhaps due to debt, the weak economy, lack of security from getting a degree etc), and have actually earned a big chunk of the upward grade adjustment. That's certainly been my experience when compared to my own cohort, and that of quite a few professors that I talk to as well.