A statistical case against points-based grading
"The problem is this: Although we treat points like numbers and do statistics on them like numbers, points are best understood not as numerical data but as ordered labels. And therefore the statistics we perform on them make no sense."
I love this.
This is brilliant. I love it. Thank you for such a clear explanation of why we shouldn't use points (or %).
This is a great article and I am convinced by many of your arguments. Re arguments in favor of points-based grading, though, one thing that I think about a lot for my grading system is transparency--students should be able to compute their grade themselves at any point; other than very late-semester grades (e.g. final projects or, god forbid, exams) there should not be any suspense or surprise about their final grade. (I think this is important for giving students a greater sense of ownership over their learning and grades, and hopefully decreases perceptions that grades are arbitrary (which admittedly to a certain extent they are) or capricious (which hopefully they are not). Points-based grading makes this very easy; simply add up points according to a certain formula (which, in math classes, can even be reasonably complicated, or available by a public excel sheet or similar). I know not everyone values this sort of transparency to the extent that I do, but do you have any suggestions about how to maintain transparency in the absence of points (or arguments that it's worth sacrificing it)?
The ordinal/scalar question is nuanced. See an analysis of "optimal" grade point weighting under certain assumptions here: http://highered.blogspot.com/2021/12/are-you-calculating-gpa-wrong.html
Robert, I appreciate you making this argument as strongly as you can. I agree partially. Regarding your statement "There is simply no argument for using them other than inertia," what you're calling inertia might include the fact that, for a lot of us, it makes intuitive sense to give final grades as a weighted average of individual assignments. I think you're saying that we shouldn't average things that shouldn't be averaged, but we can often make the math work OK if we include tricks like dropping the lowest grade (to deal with that one 0 dragging everything else down). If a student has 3 big tests and gets scores of 65 (D), 75 (C), and 85 (B), it seems reasonable that their final grade should be in the 75/C range. Contrast that with three big units of a standards-based grading course where a student met all the standards for one or two units, but not the third unit. Is that B work, or C work, or ... ? Reasonable decisions can certainly be made, and justified, but that can feel more arbitrary and less intuitive than the weighted-average approach. Thus, to make a completely successful argument against points-based grading, you may need to confront the intuitive appeal of weighted averages even more directly than you did in this post.
How does one evaluate and improve a course that uses a specifications grading system?