By default, my quizzes are automatically set as points in their grade columns, and I see no option to change them to percentages. This creates a mathematical problem because my assignments are set as percentages (the way I want all my grade columns. How do I change an existing quiz column in grades from points to percentage?

Keith,

If you want your quizzes to display as percents, you make them worth 100 points by adjusting the point values within the quiz. Legacy Quizzes only display how many points they are worth, they cannot be displayed as a percentage, complete/incomplete, or letter grade. There was a feature idea for the old quizzes Show quiz as percent score in Gradebook that has been marked as complete. The reason it's complete is because of Quizzes.Next, not because the older version supports it.

You're probably not using Quizzes.Next, though, or you most likely wouldn't be asking the question.

That also doesn't help with an existing completed quiz, so I'd like to focus on your other statement.

What makes you think that it creates a mathematical problem?

Displaying the assignment as a percentage does not change the way the calculations for the grade are made. The calculations for assignments are based on the point values, even if you display it as a percentage (or a letter grade, complete/incomplete, or points).

If you have a 10 point assignment where the student scores 80% and a 30 point assignment where they score 60%, then their grade is not 70% (the average of 80% and 60%). 80% of 10 is 8 and 60% of 30 is 18. So they scored 26 out of a possible 40 points and their grade is 65%. The weighting is accomplished by the point value of the assignment.

Now pretend that one of those assignments was a quiz. It doesn't matter to Canvas, it calculates the grade the same way. If you want to count all assignments equally, then they need to be worth the same amount of points. For quizzes, that means setting the point value on the quiz to same as the other.

You probably don't want the quizzes to count the same as everything else, though. Now you're getting into the area where displaying grades as percentages can be confusing to students. I had a 50 point midterm this semester. I could have displayed it as percentage and students probably would have appreciated it at the time when it was the only grade in that category. However, there's also a final in that category and it's worth 100 points. If I display them both as percentages and they are not equal in value, then students are going try to average the two percents together rather than considering the weights. I had a student who asked me why I hadn't graded an assignment because she didn't realize the checkmark meant she got full points for a complete/incomplete assignment. I can just imagine the students asking why an 80% on the midterm and a 50% on the final is a 60% instead of a 65%?

I have not used Quizzes.Next, but the new version of Quizzes is treated more like an assignment and you can choose to display the value as a percentage just like with any other assignment. See How do I create an assessment using Quizzes.Next? for more information.

For the current quizzing system, though, you're either going to have to fake a percentage by making it worth 100 points or live with the point value. If your quizzes are in an assignment group by themselves, you use a weighted gradebook, and you want all the quizzes to count the same, then there is no problem (for new quizzes) making them worth 100 points. If any of those is not true, then you shouldn't do that.

None of that fixes the issue with an already completed quiz. Some question types can be automatically regraded: What options can I use to regrade a quiz in a course? However most cannot be. There's also a note at the top of that document that says if students have completed the quiz, then changing the point value doesn't trigger a regrade and the updated score won't show up in the gradebook.