How Does the Grade book Calculate Grades?

How Does the Grade book Calculate Grades?

by Jedidiah Rex -
Number of replies: 2

Moodle 2.9.4 (Build: 20160111)

Instructors brought to me a question about how the Gradebook calculates the grades. When they attempt to replicate the calculation outside of Moodle on their own, the results are different. It is also unclear how Moodle is arriving at the calculated weight. How is this calculated? In both instances, the course aggregation is set to Natural. The categories are also set to Natural.

As examples:

Scenario one - the instructor calculates a student's current overall grade to be 82.9%, but the grade book has the grade at 77.47%.

Scenario two - The weight for a particular category is 15% in the setup. The calculated weight is displayed in the User report for that category at 17.65%. Why the disparity? How is Moodle arriving at this number?

Please let me know if other screenshots will be helpful.

Attachment mdl grades-calc_sc1-cats-items.png
Attachment mdl grades-calc_sc2-user-report.png
In reply to Jedidiah Rex

Re: How Does the Grade book Calculate Grades?

by C Behan -

Hi Jedidiah,


A quick thought ... I didn't do any sums to check but ... could it be that empty grades are excluded from calculations? That's one easy way of skewing figures.


Catherine

In reply to Jedidiah Rex

Re: How Does the Grade book Calculate Grades?

by Emma Richardson -
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I believe the gradebook is adjusting because there are some items that have not been attempted yet that have a weight to them.  So for the purpose of the grade right now, the gradebook is showing how much weight that category carried towards the grade at hand.  Because Final Group projects are excluded, it would make sense that their weights were excluded to.  Otherwise, students could never receive over 85% until the final project was completed.

As to comparing with their excel sheet, without knowing how they calculated that, it is hard to tell.  The gradebook will divide total points possible by total points attained to reach the percentage (then multiplied by weight if weighted).  I have had teachers report that before and have always been able to get the gradebook within a percent of their calculations (sometimes rounding up skews off just a hair) - normally, it is a mistake in the gradebook setup.