Correct error in grading rubric

[Rikst]

I made an error in the grading rubric for the final paper. I’d like to know what happens if I change it, with people already having strated their grading.

It’s two errors, actually: 1) the text for ‘ good’  is the same as the text for ‘ excellent’  and 2) there should be sliding scale instead of a fixed mark per rubric.

In the past I made such changes but since it’s such a large course and so many people / students are involved I want to make sure my changes won’t cause any of the grades getting lost. How do we adjust the grading rubric and keep the existing grades?