Moodle

Field report of computation problems in grade import into 1.9 gradebook

Details

  • Type: Bug Bug
  • Status: Closed Closed
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: 1.9
  • Fix Version/s: 1.9
  • Component/s: Gradebook
  • Labels:
    None
  • Affected Branches:
    MOODLE_19_STABLE
  • Fixed Branches:
    MOODLE_19_STABLE

Description

Martin D. has identified a priority of the 1.9 gradebook to be that on import, the computation of categories and course totals remain consistent:

Here were the anomolies of my Fall Advanced Algebra course that we moved to 1.9 last week in order of importance.

1. Categories and totals had been computed based on (points earned)/(points possible) as is standard through 1.8 (and how teachers typically compute grades by hand). The 1.9 Beta 2 computed these values using "normalized mean of grades" which converts values to percentages before computing averages (non-standard). This meant that all the categories and course totals were wrong. Changing these to what is now called "Simple Weighted Mean of Grades" fixed this problem for most categories and the category sumaries in those cases were the same.

2. I use a common scaled called "Not Submitted/Submitted". Through 1.8 this was not factored into the grade. On import, these were factored in, apparently worth 1 or 2 points each. When I removed these from the 1.9 import, grades changed, they should not have.

3. There were 4 hidden, 1 point sample quizzes in the homework category. When these were removed from both gradebooks by moving out of categories, the homework grade and course totals were now correct. This means that hidden grades are not being computed in the same way.

4. Couse totals to two decimal places were the same in most cases. For a couple of students. the rounding was different with the previous version being higher (95.39 vs 95.38). We can probably live with this if it were the only problem, but some may still have an issue with rounding computations as it could move a student to a different course grade.

5. Category totals and course totals should be displayed as percentages as they are in 1.6 (at least for my course). With the import, it is printed as points out of 100. A small difference, but this probably should carry over.

Hopefully this helps get the migration to the new gradebook down right.

-Gary
Gary Anderson
Math Department Chair/Moodle Master
Seattle Academy

Issue Links

This issue is blocked by:
MDL-13617 META: Restore from 1.8 to 1.9 - Missing Gradebook Information Major Closed
This issue has a non-specific relationship to:
MDL-13731 problem with 1-point and/or hidden grade items Minor Open
MDL-14094 1.9 Gradebook Inaccurate when Converting 1.8 Grades Major Closed

Activity

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Martin Dougiamas added a comment -

Thanks very much, Gary.

Petr can you look through these and see what would be necessary to do today.

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Martin Dougiamas added a comment - Thanks very much, Gary. Petr can you look through these and see what would be necessary to do today.
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Petr Škoda (skodak) added a comment -

1/ we could make some simple scripts that change aggregation types in all existing courses

2/ category aggregation includes scale items too, we can not change it now - they have to be placed in separate category - solution could be to create new script that goes through all courses and moves the grade items with given scale into new category with no grading

3/ hidden grades are aggregated - we had a discussion with OU already, the problem is that we have only one final grade which does not depend on visibility - this could be improved in 2.0 because it requires db changes

4/ we are doing more numeric operations with grade values - I guess thisis the result

5/ again post upgrade script that fixes this could be made

I guess we need a new page in admin settings with migration related tweaking...

Show
Petr Škoda (skodak) added a comment - 1/ we could make some simple scripts that change aggregation types in all existing courses 2/ category aggregation includes scale items too, we can not change it now - they have to be placed in separate category - solution could be to create new script that goes through all courses and moves the grade items with given scale into new category with no grading 3/ hidden grades are aggregated - we had a discussion with OU already, the problem is that we have only one final grade which does not depend on visibility - this could be improved in 2.0 because it requires db changes 4/ we are doing more numeric operations with grade values - I guess thisis the result 5/ again post upgrade script that fixes this could be made I guess we need a new page in admin settings with migration related tweaking...
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Martin Dougiamas added a comment -

Gary, can you clarify: was this on upgrade, course import or restoring a backup? What version was it orginally?

Show
Martin Dougiamas added a comment - Gary, can you clarify: was this on upgrade, course import or restoring a backup? What version was it orginally?
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Gary Anderson added a comment -

Hi: This was an update of a course that I taught Fall trimester(we switched to 1.9 from 1.6 shortly after the start of Winter trimester – early December).

Note that in 1.9, changes have been made so that courses default to Simple weighted mean of grades (from the old (normalized) Mean of grades. So at least within categories, aggregation within categories might work differently now for #1.

Show
Gary Anderson added a comment - Hi: This was an update of a course that I taught Fall trimester(we switched to 1.9 from 1.6 shortly after the start of Winter trimester – early December). Note that in 1.9, changes have been made so that courses default to Simple weighted mean of grades (from the old (normalized) Mean of grades. So at least within categories, aggregation within categories might work differently now for #1.
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Permalink
Martin Dougiamas added a comment -

So you had a 1.6.0 site, and upgraded it all to 1.9?

Show
Martin Dougiamas added a comment - So you had a 1.6.0 site, and upgraded it all to 1.9?
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Martin Dougiamas added a comment -

re 2) we could possibly change courses to use "Weighted Mean of Grades" by default and use weights to remove the scale items but is that a good idea really?

Show
Martin Dougiamas added a comment - re 2) we could possibly change courses to use "Weighted Mean of Grades" by default and use weights to remove the scale items but is that a good idea really?
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Gary Anderson added a comment -

Our school's patches diverged far enough that we stopped being CVS compatible around 1.6.3 or so.

For our final transfer, we went from 1.6.3 to the latest 1.7 to 1.8 and then to 1.9 (not something I would recommend now – I would just go from 1.6.x to 1.9 when updating.)

During this process, our gradebook gave the same computation at the 1.8 point and diverged as above for 1.9.

Show
Gary Anderson added a comment - Our school's patches diverged far enough that we stopped being CVS compatible around 1.6.3 or so. For our final transfer, we went from 1.6.3 to the latest 1.7 to 1.8 and then to 1.9 (not something I would recommend now – I would just go from 1.6.x to 1.9 when updating.) During this process, our gradebook gave the same computation at the 1.8 point and diverged as above for 1.9.
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Permalink
Petr Škoda (skodak) added a comment -

I have moved out the hidden item issue subtask, the rest should be already solved in 1.9

thanks for the report and cooperation

Show
Petr Škoda (skodak) added a comment - I have moved out the hidden item issue subtask, the rest should be already solved in 1.9 thanks for the report and cooperation

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Dates

  • Created:
    Updated:
    Resolved:
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