Blame the bell curve


The semester’s over and you’ve just had your soul crushed by ROSI telling you your final mark in a course. You were sure you’d do better. You murdered that final exam. You turn to your friend, you shake your head, and you say, “They bell-curved the marks. That’s why I didn’t do as well as I expected.”

On Internet forums and in the mutterings of frustrated students, U of T is notorious for bell-curving down, but most students have never really received any confirmation of this. In fact, many of us may not even be clear on what bell-curving is.

There are many ways to bell-curve grades. One of the most popular methods is to statistically determine how many people in each class will get a certain grade and then mathematically slot students into those groups. For example, a professor or department would estimate that 10% of students will get an A, 20% will get a B, and 70% will get a C. The grades the students actually received then become a ranking system. That ranking system is used to separate the students into the predetermined A, B, and C grade groups. Depending on where you stand academically, this could sound awesome or just plain cruel.

According to Office of the Dean, though, U of T does not adhere to this system and does not encourage its professors to use it either. “We feel the grades students earned should be accurately reflected in their final grade,” said UTM’s vice-dean, Kelly Hannah-Moffat.

“Typically, we see grades sequestered in the A, B, C range, and we ask professors to determine the percentage of grades, and if something looks unusual we ask for an explanation.” Hannah-Moffat expects that other Canadian universities don’t use a curved grading system either.

But Hannah-Moffat, who is also a professor of sociology, also believes that professors use their students’ grades to reflect on the course. “There are times when people write a test and everybody does awful, and you have to really think hard about if you taught the material properly—or did people not study?” she pointed out. But even in those cases, she repeated, the professor is still not required to adjust the grades according to university policy.

So is avoiding bell-curving useful to students? “[Not adjusting students’ grades] is advantageous because it’s an image of their work, and people at the top end of the spectrum need to be rewarded,” said Hannah-Moffat. “I think it’s important to accurately affect the students.”

Speaking to several different professors on campus, it’s interesting to see how individual departments and professors grade and how they feel about grading methods.

“There’s no enforced bell curve, as I understand it,” said Ira Wells, who teaches American literature. “I don’t have to give a certain number of grades. There’s an expectation in any class: about 25% will be Cs and As. That’s not anything that’s enforced; that’s just how it works out.”

I asked Wells how he thinks adjusting grades affects students and how he thinks they view bell-curving.

“Your opinion of the bell curve is going to relate to what you think university is for,” he said. “So if you think that university is for giving everyone access to certain skills, about bringing everyone up to a certain standard, then you might not think that the bell curve is such a great idea. You don’t want to expect certain outcomes if it’s about equalization. That’s only one way of looking at what university does. The other way is to sort people out. University is a natural sorting mechanism for who is going to be where in the hierarchy.

“Regardless of what I think, it does both,” he added. “If I could give As in all my classes, grades would be meaningless.”

Jonathan Weisberg, a philosophy professor, said the philosophy department does not bell-curve grades. “I don’t use a bell curve specifically, but I do keep track of how many students are getting As, Bs, Cs, etc.,” he said. “I also keep an eye on statistics like the average and the median as the semester progresses, and of how many students are failing. These statistics help me understand how students are responding to the material.”

Does Weisberg believe that the bel- curve is a useful tool for grading? Not necessarily.

“I think it’s important to give people the mark they earned, a mark that reflects how well they’ve mastered the relevant material and skills,” he said.

The departments don’t necessarily adhere to bell curving, it seems. But how do students feel about their grades?

“Beyond the obvious con of being at the bottom of the bell curve, I’m curious as to what average determines if a course gets the bell curve,” said Mary Cho. “Some courses will be really hard, and if people do well, the bell curves to the expected average. I don’t necessarily have any pros or cons, but more I’m concerned with the reasons as to why a course may be bell-curved.”

So we know that the university doesn’t mandate bell-curving, but we also know that some professors occasionally use it. At least we can all sleep at night knowing it won’t necessarily happen to all of us.

We will, however, have to come up with another excuse when we don’t meet our own grade expectations. Maybe we can use the other old standby: “Obviously, the professor hates me.”

  • C.I.

    Important note of clarification: “curving” doesn’t mean raising or dropping the average on an exam or assignment. It means correcting the distribution. If a class is at 60 and we want it to be 70, you probably aren’t adjusting it through curving. (Possibly, but probably not – if you’re just bumping everyone up 10 points, which is the easy option, you’re not curving. Also, curving is hard.)

    On the other hand, if 50% of students have a D and only 10% have an A or B, applying a bell-curve would probably push many of those Ds into C territory, and many of the Cs into the B territory – so that the distribution looks bell-shaped. It may only have a small effect on the overall average and a significant effect on only the extreme outliers, and thus escape notice altogether. Because that’s what the bell-curve does and how it works.

    So, you might have been asking the wrong question. Because – guess what? – departments and professors adjust their grades all the time. (It’s usually in the students’ favor, though, since it would be easy for you to petition a grade if they unilaterally lowered them from what you KNOW you earned. If, on the other hand, your grade is higher than expected, you’re not likely to complain.) But, for the most part, instructors just don’t use bell-curves.