Gradebook inaccuracy

Gradebook inaccuracy

by Edward Burke -
Number of replies: 2

Hello all

I’m using Moodle 2.8.5  I have a faculty member running a weighted gradebook. GB is set to not aggregate empty grades. I have a category entitled TESTS that is set to Simple Weighted Mean.  I have 2 tests in that category  Test 1 has a 10 point max grade  Test 2 has a 20 point max grade.  When I enter test 1 scores everything is good  9 out of 10=90  BUT when I enter the test 2 scores, the GB does not calculate properly.  Ex test 1 = 9out of 10=90  test 2 = 16out of 20=80.  When placed in the GB the category total is NOT 85 as you would expect, it is 83.33.  I’ve deleted/recreated the test category---same result.  I’ve looked at the test settings to see if there was a multiplier at work…nothing unusual or different between test 1 and test 2 My workaround at the moment is 2 test categories, splitting the weight (20%) so that the students can get an accurate grade at this moment, but this is not the solution.  Any help is appreciated


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In reply to Edward Burke

Re: Gradebook inaccuracy

by Floyd Saner -

Edward,

I have never encountered incorrect calculations in the recent Moodle grade book. If you provide a screen shot or a temporary teacher login someone in this forum might be able to help.  Every case like this that I've worked on was solved by changing some settings, not by creating a work-around solution.

Floyd

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In reply to Edward Burke

Re: Gradebook inaccuracy

by Ryan Hazen -

With Simple Weighted Mean, Moodle GB is weighting the 20 point assignment at twice the weight of the 10 point assignment, because SWM uses point value as the weight for the item. If your intended result is 85, change the aggregation to "mean of grades," which will normalize the grades (represent them all as decimals, or percentages) before averaging them. That should give you 85. 


In other words, you're getting 83.33 because the 20 point assignment is worth 2/3 of the total grade (20 out of 30 points altogether), and that's the one that is at 80%.

Average of ratings: Useful (1)