This idea involves creating a new grading scheme type, the Min-Max numeric grading scheme, to support numeric grading schemes worldwide without any rounding errors. Also the GPA scale can be facilitated with this idea, also without any rounding errors.
The current grading scheme method originates from the need to translate assignment points to a text based grading standard such as A to F. This translation is done by defining ranges of percentages of points for each letter grade. The same method is used for the GPA grading scheme (0.0 tot 4.0).
The problem using a collection of ranges to match a numeric grading standard is unnecessary rounding errors.
To minimize the rounding errors a 0.0 to 10.0 scale needs 101 ranges to be defined:
(these ranges have a margin of 1%)
The big question is, why not eliminate the ranges entirely for number bases grades (even GPA?) and have a direct calculation from points to the the numeric grade:
Numeric grading standards worldwide
Just to name a few:
(source: Grading systems by country - Wikipedia)
The design of the Min-Max numeric grading scheme
The new Min-Max numeric grading scheme works without ranges, but supports the direct and precise calculation from points to the grade of the selected grading standard. The Min-Max numeric grading scheme applies to the individual assignments (see How do I add a grading scheme to an assignment?) and also to the course level (see How do I add a grading scheme in a course?).
Creating a new Min-Max numeric grading scheme (mock-up)
Selecting the Min-Max numeric grading scheme in the assignment settings:
Selecting the Min-Max numeric grading scheme:
Creating / editing the Min-Max numeric grading scheme:
Capabilities and properties of the Min-Max numeric grading scheme
- Ability to define the range by setting a minimum value (low) and a maximum value (high).
- 5 (min/low) to 10 (max/high)
- 5 (min/low) to 1 (max/high)
- 1 (min/low) to 10 (max/high)
- Have it accept decimals behind the decimal separator with the options:
- Setting a limit for the amount of decimals
- Display of decimals:
(e.g. with 2 as limit, entering 7.00 or 7 will show as 7 and entering 6.35 will show 6.35)
- Fixed amount
(e.g. with 1 as limit, entering 7 or 7.00 will show as 7.0 and entering 6.35 will show 6.4)
- Checkbox Limit grade when exceeding total points to keep the grade within the Min and Max.
(e.g. while grading and more points are given than the total amount of points of the assignment, thus more than 100% of the total points)
- Use precise rounding methods
(e.g. when using weighted assignment groups or when using it as course grading scheme)
If Min < Max Then
Student grade = Min + ( Absolute ( Max – Min ) / Total points * Scored points )
Student grade = Min – ( Absolute ( Max – Min ) / Total points * Scored points )
Display grade = format ( Student grade ; desired decimal count )
Simulation of the Min-Max numeric grading scheme
In the attached Excel sheet you can experiment with the Min-Max numeric grading scheme, by:
- Setting the assignment points
- Scored points
- Amount of decimals
- Variations in numeric grading standards
- Seeing the effects of the calculations