Canvas Selecting Wrong Letter Grade on Assignment When Values too Narrow

[KurtisBonano]

I have created the letter grading scheme below. I want to give students a 4.1 on their assessments to show that they exceeded (A+) expectations.

In the past, I would give students a 5 instead of a 4.1, but that pulled their overall grade up too much and they could slack on later exams. I want students to have to exceed (A+) expectations on most of their exams to exceed (A+) overall in the course. The issue I have is shown in this screenshot of the gradebook:

Students who received a 4 on the exam are showing up as having an A+ when their numerical score is a 4/4.1. I can see that Canvas knows this because there is only one assignment in that category and the scores I input are showing up correctly. When I check on their overall grade which is calculated using this scheme:

it is also displayed correctly. e.g. students who received a 4 on the exam have an A in the class, and those who received a 4.1. As I wrote out this part of the post, I realized I can just adapt the overall course grade and it will work for this.

Now I just want to know, is there a minimum spacing between grade bands? I played around with the grading scheme at the top of the post, and even changing and A to <4.1 to 3.9 still didn't do the trick.

[chriscas]

Hi @KurtisBonano,

I haven't been able to investigate the code behind the grade schemes, but I believe Instructure calling something a "points" based scheme is probably a bit misleading and can cause some confusion.  As far as I can tell, the point-based schemes were really just created to try to help faculty avoid having to do math to convert points into percentages, but they actually do work just like (and may be converted to) percentages in the background, and not just raw points...  This would also explain why point-based schemes can't go above 100 points, because everything actually is a percentage-based thing, and having huge points scales could mess up the math (if 1,000,000,000 points was an A, 999,999,999 points was a B, and 999,999,998 points was a C, etc. converting these back into a percentage with rounding would mean many of the letters would never be possible.

You can test this yourself...  If you take your 4.2 point scheme and apply it to an assignment worth only 3 points, you'll see that awarding 3 points equated to an A+, because it's not the raw points, it's a percentage.  I do also think there is some rounding/truncating that happens somewhere, but I don't know exactly how many decimal places (I assume 2 based on the UI behavior, entering 99.99% works but 99.999% changes to 100) and whether it's rounding or truncating at any or all of those points...

So in the end, I think the minimum spacing between bands would be 0.01%, but how that plays out for points depends on that back-end conversion to percentage math. 

I did also want to point out that in your first example, because of the way the points-based schemes seem to really be percentages in disguise, you did have some weird math going on behind the scenes, because you applied the 4.2 point scale to an assignment worth 4.1 points, which was probably causing some of the confusion.  Your second point scheme is functioning "better" perhaps because the max points you used is 4.1, which aligns with the assignment being out of 4.1 points.

I hope this post helps a bit and that I haven't caused even more confusion or missed any important details...

-Chris