Help with including both letter grades and numeric grades in a category total

Help with including both letter grades and numeric grades in a category total

by Edwinna Lucyk -
Number of replies: 8
I have some assignments that receive grades using a letter grade scale and some that use a numeric scale. I have chosen simple weighted mean as the aggregation method but I cannot arrive at the same number for the category total that the gradebook calculates.

How does the gradebook add in the letter grade?

I have tried adding in the upper bound for the letter grade, the lower bound for the letter grade and the average of the upper bound and lower bound but cannot come up with the same number that the gradebook calculates.

Any help would be most appreciated.
In reply to Edwinna Lucyk

Re: Help with including both letter grades and numeric grades in a category total

by Vicki Dunnam -
I have added a column where the computer takes the course total and displays it as a letter grade.  I am not sure how the computer can calculate with a mixture of letter grades and numeric grades in the gradebook.  If you need assistance on showing the letter grade, just let me know. 
In reply to Vicki Dunnam

Re: Help with including both letter grades and numeric grades in a category total

by Edwinna Lucyk -

Thanks for the reply.  I can display letter grades but cannot match the gradebook calculation when some assignments use letter grades and some use numerics.  I for example used 97 for an A+ and an 87 for a B+ to do my hand calculations.  The gradebook calculation is actually within a point of what I get when I do it by hand.  I just can't explain the discrepancy.  I am trying to find out exactly how the gradebook uses letter grades when it does its calculations.
In reply to Edwinna Lucyk

Re: Help with including both letter grades and numeric grades in a category total

by Roger Brüderlin -
Probably the problem is, that moodle calculates the letter grades (and all other grades, even those based on numeric scales) on the basis of percentages.
I encountered a similar problem when I wanted to show my students their final grade as a mark (swiss marking system, minimum 1, maximum 6). I generated letter grades from 1 to 6 in steps of one tenth. The final grade should be calculated as a simple mean from marks (letter grades) of tests. When I entered the shown letters/marks of the tests in the gradebook in an excel-spreadsheet, the final mark (mean) was slightly different from the one moodle calculated, but relevant for the final mark a student gets (because of mathematical rounding to steps of one half, e.g. 4.5, 5, 5.5 etc.).
I then switched to show every value in the gradebook table as a percentage and the calculations matched exactly the ones made by hand. That's what leads me to this suggestion.
Hope, this explanation and my english is clear enough and matches your question… as it is my first forum contribution here…zwinkernd
In reply to Roger Brüderlin

Re: Help with including both letter grades and numeric grades in a category total

by Edwinna Lucyk -

Thank you for your reply. (Your English was perfectly clear by the way.)
I tried changing every grade in the gradebook table to display as a percentage.  When I averaged those percentages by hand, they still did not match the gradebook average although they were within a few points.  The letter grade scale used for one assignment was a scale that ranged from A+, A, A-, B+, B, etc to F with 11 grades in all.  When I looked at the percentages, MOODLE had substituted a 100% for an A+ but a 70% for a B+.  I am guessing that MOODLE assigned grades in increments of 10 from 100 for an A+ down to 0 for an F.  That explains the 70% for the B+ but that is only a guess.  My problem is that even averaging in that 70% with the other assignments which had numeric grades (in percentages), I cannot come up with the number the gradebook did.

Do you know of any documentation of exactly how letter grades are accounted for in the aggregation process?

In reply to Edwinna Lucyk

Re: Help with including both letter grades and numeric grades in a category total

by Nicolas Connault -
Edwinna,

You can setup the values associated with letter grades yourself. I am attaching a screenshot showing the location of the menu item that will open the "Letters" edit page. These are set up site-wide by default, but can be overridden per-course using this interface.


Attachment gradebook7.png
In reply to Nicolas Connault

Re: Help with including both letter grades and numeric grades in a category total

by Edwinna Lucyk -

Nicholas,

I did set up the letter grade ranges on the site level but still do not know which value in the range is used when a particular letter grade is aggregated with a numeric grade.
Also, when I set the letter grade bounds, I do not have the ability to specify a 93.99% for example.  I can only specify whole percents from a drop down list even though I have 2 decimals specified in the settings.  How did you get that ability?

Edwinna

In reply to Edwinna Lucyk

Re: Help with including both letter grades and numeric grades in a category total

by Nicolas Connault -
Edwinna,

You do not enter grades as Letters. You enter them as raw grades (delimited by the item's minimum and maximum grades), then they are converted in grade letters for display purposes only. The grades are not stored as letters in the database.

When you edit grade letters, you only specify the letter grade's lower boundary. The lower boundary is always set to the next letter's (upward) lower boundary, minus 0.01.
In reply to Vicki Dunnam

Re: Help with including both letter grades and numeric grades in a category total

by Tim Duruz -
Vicki,

What I did, was set the COURSE GRADE as a Letter Grade. I also made a single CATEGORY that had all the assignments in it, including all weights, and this displays as a PERCENTAGE.

Inelegant, but for now it seems to be reasonably effective.

Regards,

Tim
aka 'perfesser'