Strange Calculations in Gradebook

Picture of Ed Watson
Strange Calculations in Gradebook

I have a scenario where a faculty member has created a scale that looks like this:


Unacceptable, F/F, F/D-, F/D, F/C-, F/C, F/C+, F/B-, F/B, F/B+, F/A-, D-/F, D-/D-, D-/D, D-/C-, D-/C, D-/C+, D-/B-, D-/B, D-/B+, D-/A-, D/F, D/D-, D/D, D/C-, D/C, D/C+, D/B-, D/B, D/B+, D/A-, D+/F, D+/D-, D+/D, D+/C-, D+/C, D+/C+, D+/B-, D+/B, D+/B+, D+/A-, C-/F, C-/D-, C-/D, C-/C-, C-/C, C-/C+, C-/B-, C-/B, C-/B+, C/A-, C/F, C/D-, C/D, C/C-, C/C, C/C+, C/B-, C/B, C/B+, C/A-, C+/F, C+/D-, C+/D, C+/C-, C+/C, C+/C+, C+/B-, C+/B, C+/B+, C+/A-, B-/F, B-/D-, B-/D, B-/C-, B-/C, B-/C+, B-/B-, B-/B, B-/B+, B-/A-, B-/A, B/F, B/D-, B/D, B/C-, B/C, B/C+, B/B-, B/B, B/B+, B/A-, B/A, B+/F, B+/D-, B+/D, B+/C-, B+/C, B+/C+, B+/B-, B+/B, B+/B+, B+/A-, B+/A, A-/F, A-/D-, A-/D, A-/C-, A-/C, A-/C+, A-/B-, A-/B, A-/B+, A-/A-, A-/A, A/F, A/D-, A/D, A/C-, A/C, A/C+, A/B-, A/B, A/B+, A/A-, A/A
Where the Content grade is the part of the grade before the forward slash and the Communication grade is the part after the forward slash. 
When the faculty member places these grades in the gradebook it is coming up with some sort of sum calculation. I do not understand how it is caluclating this value.
For example: B-/A- = 64.00% and B/B = 71.20%
As you can imagine when the students see this calculation they are freaking out.
Any help with this would be greatful, since it is driving me crazy trying to figure it out.
Thanks, Ed
Picture of Emma Richardson
Re: Strange Calculations in Gradebook
Group Documentation writersGroup Particularly helpful Moodlers

Could it be that it is as simple as the program is dividing the first number by the second number?

I can't imagine how this grade scale would work correctly - I think that he might be better just to set his gradebook up with categories that are then weighted appropriately.

I may be wrong but I am pretty sure there is no way to make a dual grade like this work.

Picture of Ed Watson
Re: Strange Calculations in Gradebook

That is what I was thinking. Just can't seem to make the math come out correctly.

When I saw what they were doing, I was concerned that it would not work either.

I suggested the same thing. Set up a catagory that would display the grades they are wanting to use A/B-, but to then edit weighted outcome to achieve the desired percentage grade.

Thanks for the reply. I thought that I was missing something.

Rock climbing
Re: Strange Calculations in Gradebook

The grade is being calculated because values entered in a scale are seen as strings of text and then calculated based on the total number of possible values. As an example, a scale of "F, D, C, B, A" is the same as "Cat, dog, fish, bird, elephant". The value choices are simply selections you can choose from; that are then displayed to students.

The grades/percentage that is then displayed to students based on what value choice was selected, is dependent on your aggregation type. So in your example scale, there are 126 different choices to select from. If a student was given "F/A-", that is the 11th choice from the bottom of the list. This means Moodle is going to convert it to 11/126 or 10/125 depending on your aggregation type.

As a personal recommendation, I have my faculty users avoid scales because most do not understand what a string of text means. Some have created scales like "0, 1, 2, 3" or "3, 2, 1, 0". Both are the same in that they have four values. One is backwards but that doesn't matter as they are seen as strings of text. Furthermore, depending on their aggregation type, Moodle will convert these to be either 1-4 points possible or 0-3 points possible.

I recommend checking out the Moodle Docs on scales as it has some better examples than mine. If you want to allow your instructors to continue to make scales like this but don't want Moodle to convert it to a percentage and thus towards the course total, go into Site admin > Grades > General Settings > Include scales in aggregation and uncheck the box.

Happy Moodle Logooodling!

Picture of Ed Watson
Re: Strange Calculations in Gradebook

That makes complete sense now. I had a suspicion that this scale was going to cause some strange outputs, but was not sure how the value was calculated. I have looked at the scales doc before, but I guess that I was missing that part.

Thanks for the detailed answer. I have now turned off the aggregation in the settings. I will see what kind on feedback that get from them now.

I learn something new everyday about moodle.


Picture of Mark McKay
Re: Strange Calculations in Gradebook

Two thoughts on this:

  1. There is a global setting to exclude Scales in calculations, and gradebook settings to prevent percentages from showing.
  2. This would be an opportunity to use rubrics; one for content, the other for communication.