Why change a university grading scale?

LettersI recently mentioned the 2014 paper by Schinske and Tanner that is a great review on various aspects of grading, including some of the history of grading in higher education.

Schinske and Tanner highlighted the fact that grades were developed as a method for universities to communicate (e.g., between schools). This is still an important function that grades play today (within/between schools, and beyond), and there are clear benefits from having a valid, reliable grading system. In the early 20th century, percentage (100-point) scales were frequently used (Cureton, 1971).  The letter grade system adopted at Harvard was apparently a result of faculty members’ concerns about the reliability of grades measured on a percentage scale, and it was believed that a letter grade system (with 5-categories) would provide increased reliability. 

Even today, issues with reliability (as well as validity) of grading exist. (Schinske and Tanner discuss this as well.)  Thus, I found it a bit surprising last fall when the University of Windsor (where I currently teach) switched from a letter grade/point system (a 13 point scale) to a percentage system for final grades. I could understand if this shift were bringing the school’s grade reporting in line with many others in the same region (e.g., within a province or country); with different grading systems/scales used by various universities, it can be challenging to make comparisons between students from different schools for things like scholarships, professional school applications, etc. However, from my observations (and the OMSAS Undergraduate Conversion Chart), the percentage system isn’t the most widely used grading scale in Ontario, nor across Canada.

I’m not sure why the change to a percentage grade system was made. It is possible that the rationale was  provided in some form, but that I didn’t receive it, or have overlooked it. I’ve asked colleagues here, who also didn’t know. Some (quick) searching of the university website hasn’t pulled up anything helpful, but again, it could be there and I’m not finding it (as my search terms are pretty common words on a university website). Although I’ll be a bit embarrassed if someone posts a link to something that explains it, I’d still appreciate knowing!

A few questions come to mind: Why did this university change from letter grades to percentages? Is this something that has happened at other institutions? Are there schools that have recently taken the opposite approach (moving from percentages to a point system)? (From the OMSAS chart, I’m guessing that Dalhousie and the University of Toronto made changes, but I don’t know in which direction.) Have any changes in grading systems/scales been accompanied by initiatives relating to how grades are determined?

As ever, I’m interested in seeing your comments (and, hopefully, answers to some of my questions)!

Cureton L.W. 1971. The history of grading practices. NCME Measurement in Educ. 2(4):1-8. Link to pdf.
Schinske, J., and Tanner, K. 2014. Teaching More by Grading Less (or Differently). CBE-Life Sciences Education 13(2): 159-166.


2 thoughts on “Why change a university grading scale?

  1. Tamara

    Great post! I can’t even try to answer your questions (and you’ve asked some good ones). I haven’t seen any good rationales of different grading systems in terms of why we have so many different scales (some are on 12 pt scales – each corresponding to a grade point increase/decrease; some on the 9 pt scale; others a 4.0 scale or a 4.3). It makes no sense. And why do some not have an A-, whereas others don’t have an A+? It just makes for confusion and a lot of issues with students thinking they are getting the bum end of the deal with their school’s grading system.

    I’d almost prefer to see the percentage grade system being used, because you would hope that it would cut back on students asking to be ‘bumped up’ (because they were *this* close to the next grade point), BUT then the OMSAS Conversion Scale shows that percentage numbers aren’t really the absolutes we might think they are because they need to be converted to the 4.0 scale. And at different schools the same percentage translates to a different part of the 4.0 scale … this baffles me (and others I’m sure, or at least I hope I’m not the only one). If the whole point of grading is to communicate a student’s performance to the student, but also to other institutions, then we’ve failed utterly at creating a good communication system.

    This made me consider that maybe then the letter scale (if it was employed at all schools) would be great, but thinking about it I could see difficulty with figuring out the final grade based on differentially weighted assignments, which just puts us back in the same place of converting a letter grade to a number and then back again (leading to the same issues of being on the *cusp* of the next letter grade).

    I think I need a drink now.

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