Why is it impossible to accurately set ranges in Rubrics?

[jomblank]

For example, setting "Meets" with a range of 25-24 points, and then wanting to set the next range to 23-20 points. Canvas does NOT allow this. The next range ALWAYS includes the lowest number from the previous range. It makes it confusing for teachers and students alike. I see NO way to change this in Canvas settings.  So the use of "ranges" could look like this:

Developed:  25-24

Developing:  24- 20

Undeveloped:  20-0

Did not attempt:  0

This is simply not acceptable.  If the "24" in "Developing" is adjusted to "23", then the previous range changes to 25-23.

[chriscas]

Hi @jomblank,

I think you see Canvas work the way it does because every possible point value needs to be accounted for (even decimals).  I'm going to paste a screenshot from Canvas here to illustrate:

Working from right to left, the score of 0 indicates the score is in the "no marks" rating criterion.  The next box indicates a score in the range from 3 to greater than 0 is in the "Middle" rating criterion.  Finally on the left a score in the range from 5 to greater than 3 is in the "Full Marks" rating criterion.

If only whole number points were allowed, the ranges you mentioned would make sense, but taking all of the possibilities into account leads to the Canvas solution.  In your example, is a user gave 23.5 points, that would not fall into any of your ranges without some kind of truncating or rounding (which could get just as confusing).  Grade schemes in Canvas work in the exact same way for the exact same reason (I think).

I hope this explanation helps at least show why Canvas operates as it does, even if it wouldn't be your preference.

-Chris