In his Feb. 12 letter to the editor, Laurentian alumnus Mark Mancini provided three major arguments to justify the new grading system, which he urged many complaining students to get used to. It is extraordinary that all his arguments, when analyzed closely, can be used to support the percentage grading system, not the new system.
Argument 1: “More importantly, professors can (and likely still do), report grades to students in percentages on assignments. It is only the final grade that is reported to students in the letter grade, which again provides a range for students to land in. This, in my opinion, is more psychometrically accurate.”
Analysis: The percentage grade is an interval scale and the letter grade is an ordinal scale. When the percentage grade is converted into the letter grade, a lot of information is lost. When calculating a student’s GPA, the new system converts the letter grade back into an interval, 0-10 scale by adding some information which no longer exists. (Statistically, we cannot compute the mean of an ordinal scale.)
Consequently, the percentage grades submitted by the professors are distorted not once but twice in the new system. Did we say the new grading system “is more psychometrically accurate”? What is meant by “psychometrically”?
Argument 2: “Does it really matter if you get 85% or 84%? Or, does it matter more than [sic] you scored in a certain range, with a certain class of students? I would say the latter is more important.”
Analysis: No, it doesn’t matter if the grades are in percentages, because the difference between 85% and 84% is clearly negligible. However, when the new system converts 85% and 84% into letter grades, the tiny difference will become a big one, between A and A-!
This arbitrary conversion will impact students in many situations. For example, when we evaluate students’ academic performance in their application to our graduate programs, the difference between 85% and 84% is not important, and we look more closely at other factors such as motivation and academic reference to choose one of the applicants. However, when their percentages are converted into letter grades, the difference between A and A- will carry much more weight in our decisions. (I should have used the past tense now!)
Argument 3: “As a student, I would rather have that margin of error. There might be a time when you score slightly above what would be required for a B+, for example. It doesn’t matter if there is another individual who scored in the upper B+ range; you both would receive the same B+. This is a nice security trade-off in a world where grades mean everything.”
Analysis: Professors use multiple measures to evaluate their students, and they apply margins of error carefully to each of them. After these careful, responsible evaluations, the final grades the professors submit are as valid as possible, which should not be further modified by the Registrar’s office.
Students work hard to improve their grades, and even a small increase in their final grade, from 55% to 59%, from 70% to 74%, or from 90% to 95%, will bring them joy and encouragement. We professors don’t make light of such efforts by the students, and try our best to evaluate their performance as accurately as possible. It is mind-boggling that in the new grading system, 90% and 97% are converted into the same grade of A+, and a small difference between 69% and 70% is distorted into a big difference between C+ and B!
Department of Psychology
Tel: 705-675-1151, ext. 4276
Editor’s note: Letters to the editor run unedited and as they are received.