Why don't university courses report percentiles together with absolute grades?

Question

In any course in university, grades will be reported on an absolute scale, such as A+, A, B+, etc. Why don't these courses also report percentiles to indicate how hard the course was? This is very similar to what the GRE does. For example, I could be in the 95th percentile, which means that I did better than 94% of the students in the class. This would also eliminate the need to adjust grades to fit a particular distribution.

Answer 1

Actually there are many reasons that contribute to this, though as noted it isn't universal.

First, there is no real basis of comparison between courses, even in the same major, since the tests, unlike, say the GRE, aren't standardized, nor do they have enough data points for valid statistical inference. The numbers, if reported, would be essentially meaningless, though people would try to impute meaning to them.

Across disciplines the issue is even more extreme, of course. How "hard" is a Calculus class compared to one in Ethics? They can both be very hard, but it is impossible to compare them since the student activities are very different as is the basic pedagogy.

Second, and to me, vital, is the fact that introducing percentiles is a form of competitive grading that I find offensive. In my view, a student should be graded based only on their own, individual, performance. The typical A, B, ... grading scheme tries to capture this notion, even if imperfectly. If I get a C it should mean that I, individually, have some deficit, independent of what anyone else achieved or didn't. And note that the grading classifications are inherently broad and inexact as are all of the measures we use to determine grades.

One can do poorly on an exam for reasons other than lack of effort and learning. You might just have gotten too little sleep, or there is a family issue that requires your time and attention. Some instructors throw out the "lowest grade" to account for such things. Others have "fuzzy" boundaries between grade levels, giving the students the benefit of the doubt if they just "miss" a cut.

And of course, tradition plays a role. People know how to evaluate the general grades they see on transcripts from long practice. Even introducing A+ grades a few years ago caused disruption in this. Percentile grading has too much chance of being interpreted incorrectly.

Finally, implied by the above, percentile grades don't really measure "how hard" the course is, but something else. Someone has to be in the lowest percentile even if all students excel.

Don't look for completely "objective" ways to measure human performance and expect that it means exactly what the numbers seem to imply. Even Usain Bolt was sometimes slower than other runners.

Answer 2

I think your question is: Why don't we rank students?

Elite universities only accept the top few percent of eligible students. If elite universities ranked their worst students, those students would choose to enroll at a lower ranked university where they could get a better rank. Soon, elite universities would have fewer students. Elite universities don't want that, so they do not rank anyone. Certain elite business schools take this further and keep all student grades secret.

Other universities copy the elite universities.

There are also no particular benefits to a ranking system.

If your question is: Why shouldn't we rank students?

Ranking encourages competition over cooperation, which reduces student learning.

Answer 3

Some universities indeed do provide rankings in one or another manner (I know that for instance WU Vienna provides statistical information how you are doing grade-wise in comparison to other students in your year and overall).

The main reason why many (most?) universities don't is because program managers and education managers tend to think of grades not directly as a device to assess how "good" students are, but as an indicator of how well a student achieved the defined learning objectives of the course (if you barely know the minimum after the course, you get whatever the lowest passing grade is, if you achieve all or almost all of the optional learning objectives as well you get the equivalent of an A+). How well a student achieves the learning outcomes is fundamentally independent of how any other student did - it's possible that nobody excelled in a course, and it's possible that everybody learned all there was to learn. In both of these case, the fix wouldn't be to re-scale the grades, but to adjust the learning objectives of the course.

This has the added benefit that grades are more predictable for students, and there isn't inherent competition among students (especially if your university heavily builds on peer instruction, you really don't want any students to withhold knowledge from each other).