Moodle
  1. Moodle
  2. MDL-18083 META: Gradebook improvements - Stage 1
  3. MDL-17248

Gradebook miscalculates aggregates using scales (custom or site-wide)

    Details

    • Type: Sub-task Sub-task
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 1.9.2
    • Fix Version/s: 1.9.5
    • Component/s: Gradebook
    • Labels:
      None
    • Environment:
      N/A to this issue
    • Affected Branches:
      MOODLE_19_STABLE
    • Fixed Branches:
      MOODLE_19_STABLE
    • Rank:
      36665

      Description

      When a custom or site-wide scale is used in "Sum of grades" aggregation, Moodle assigns incorrect point values to those given the highest rating in the scale. Hence students may be inadvertently assigned incorrect grades when scales are used by the instructor. I have verified that this error occurs for both custom and site-wide scales, regardless of how many levels are established by the scale.

      A series of screen shots showing the problem is attached for reference (see the course total for the last "student").

      To reproduce the problem:

      1) Set up a custom scale in an empty gradebook... I used "Unsatisfactory,Satisfactory,Outstanding" - should be valued as 1, 2, 3, respectively.
      2) Create a "Grade item" that uses the scale.
      3) Set the course total aggregation to "Sum of Grades."
      4) Rate "students" using each of the possible values of the scale.
      5) Note that the aggregated score for student(s) rated at the most positive level is incorrect (that student's rating is incorrectly given the value of the next-to-highest rating instead of the highest).

      (A more complex scale, using values F, D-, D, D+,... , B+, A-, A treats ratings of A (presumably worth 12 points) identically to those rated A- (worth 11 points.)

        Activity

        Hide
        Neil Streeter added a comment -

        Any chance this could be addressed in 1.9.5? I looked into this some time ago and it seems there are some comments in the code already that address this behavior with scales being offset by one. I never got far enough in to figure out exactly the best approach to fix this issue... I will take another look...

        I would really like to see scales able to be defined as:
        Unsatisfactory[0],Satisfactory[50],Outstanding[100]

        Such that the point value can be specified for each item... We occasionally have instructors that want to distribute points across a scale in a non-uniform/non-linear fashion.

        Cheers,
        Neil

        Show
        Neil Streeter added a comment - Any chance this could be addressed in 1.9.5? I looked into this some time ago and it seems there are some comments in the code already that address this behavior with scales being offset by one. I never got far enough in to figure out exactly the best approach to fix this issue... I will take another look... I would really like to see scales able to be defined as: Unsatisfactory [0] ,Satisfactory [50] ,Outstanding [100] Such that the point value can be specified for each item... We occasionally have instructors that want to distribute points across a scale in a non-uniform/non-linear fashion. Cheers, Neil
        Hide
        Petr Škoda added a comment -

        Confirming, there is a bug in sum agg when scales used.

        Show
        Petr Škoda added a comment - Confirming, there is a bug in sum agg when scales used.
        Hide
        Petr Škoda added a comment -

        fixed in cvs, thanks a lot for the report

        Show
        Petr Škoda added a comment - fixed in cvs, thanks a lot for the report
        Hide
        Nicolas Connault added a comment -

        Verified. Thanks.

        Show
        Nicolas Connault added a comment - Verified. Thanks.

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            Dates

            • Created:
              Updated:
              Resolved: