In the extra assignment column, why do some students' grades (on a large end-of-terms group assignment) appear halved (i.e. 40.5 for an 81 that was entered elsewhere?
Thanks for any ideas!
If "extra assignment" is an assignment group and you're talking about the summary percentages at the end of the gradebook, then the most likely culprit is that you have an extra assignment in that assignment group and it has 0 points entered for some students.
If, for example, you have extra credit 1 (worth 100 points) and extra credit 2 (worth 100 points) and then student turned in the first one, and got 81 points, but they didn't turn in the second one and you put in a zero, then they would have
(81+0)/(100+100) = 81/200 = 40.5%
If you are using the legacy gradebook and have the options to "Treat ungraded as zero", then you don't even have to have put a 0 in for the student, it's doing what you told it to do. That option to treat ungraded as zero is very confusing and most people think it means something other than what it does, which may be part of the reason that Canvas removed it from the new gradebook.
I would go to the Assignments page, find the "extra assignment" group, and see what assignments you have in there.
If "extra assignment" is an assignment instead of an assignment group, then you most likely have something else in the same assignment group as it. What I wrote above still applies, go to the assignments page and find the group with the "extra assignment" in it and see what else is in that group and that's the most likely culprit.
If you mean something completely different, you're going to have to include more information about what you mean by the "extra assignment".
I do not use weighted assignment groups, and so am not an expert but expect that is the problem - without being able to look at everything else in your course.
There is a nice explanation of weighted assignment groups at How do I weight the final course grade based on assignment groups? that does explaing the impact on individual assignment scores.
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