(This article was originally published at Statistical Modeling, Causal Inference, and Social Science, and syndicated at StatsBlogs.)
My upstairs colleague Blattman writes:
The trend is unsurprising. Schools have every incentive to move to the highest four or five piles [grades] possible. . . . Then grade inflation will stop because . . there will be nowhere to go. . . . So why resist the new equilibrium?
I don’t have any argument for resisting, but I don’t think everything’s quite so simple as Chris is saying.
First, you can easily get compression so that almost everyone gets the same grade (“A”). So, no four or five piles.
Second, the incentives for grading high have been there for awhile. To me, the more interesting question is: how is it that grade inflation hasn’t gone faster? Why would it take so many decades to reach a natural and obvious equilibrium? Here’s what I wrote last year:
As a teacher who, like many others, assigns grades in an unregulated environment (that is, we have no standardized tests and no rules on how we should grade), all the incentives to toward giving only A’s: When I give A’s, students are happier and complain less, I get to feel like a nice person, and I give my own students (whom I generally have somewhat warm feelings toward) a benefit in their future lives. Back when I used to organize a class with several different section leaders, each instructor wanted to give his or her students higher grades. We had common assignments and a common final exam; even so, each instructor had a reason why his or her students deserved some exemption from the grading cutoffs.
So the real question is, why have grades been going up so slowly? I assume that back in the 1940s, a prof couldn’t really just give all A’s to his or her classes: someone would probably notice and say something. But now we really can, and it’s been that way for awhile.
The fact that profs don’t give all A’s, even though they can, is interesting to me. My explanation for this behavior is as follows: college professors typically got high grades themselves in college. Getting high grades is part of how we defined ourselves when we were students. So, now that we’re giving out the grades, we don’t want to devalue this currency. It’s not a matter of self-interest–if I give out a bunch of A’s to my students, it’s not going to retroactively tarnish my college grade-point average. Rather, I think it’s just that profs see grades as important in themselves. Sort of like rich people who don’t want to debase the currency, just as a matter of principle.
I remember looking at grading records for undergraduate classes back when I taught at Berkeley in the early 1990s. There was lots of variation in average grades by instructor, even for different sections of the same class. I didn’t do a formal study, but I remember when flipping through the sheets that average grade seemed to be correlated with niceness. The profs who were generally pleasant people tended to give lots of A’s, while the jerks were giving lower grades. Again, no standardized tests so no way to judge whether the average grades were informative, but I doubt it.
At the institutional level, these problems with grades would be fixed using standardized tests or with some sort of statistical correction such as proposed by statistician Val Johnson, who writes:
There are two approaches that might be taken in reforming our grading system. The first is to encourage faculty to modify their grading practices and adhere to a “common” grading standard. The second is to make post-hoc adjustments to assigned grades to account for differences in faculty grading policies.
The beauty of Val’s approach is that it does three things:
1. By statically correcting for grading practices, Val’s method produces adjusted grades that are more informative measures of student ability.
2. Since students know their grades will be adjusted, they can choose and evaluate their classes based on what they expect to learn and how they expect to perform; they don’t have to worry about the extraneous factor of how easy the grading is.
3. Since instructors know the grades will be adjusted, they can assign grades for accuracy and not have to worry about the average grade. (They can still give all A’s but this will no longer be a benefit to the individual students after the course is over.)
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