Daily Archives: December 10, 2008

8. Grades Should Not Be Based On The Mean.

In my Standards-Based Grading post two weeks ago, Anon Y. Mous asked that I explain the rationale behind each of the core guidelines involved in the S.B.G. system. I think it’s a good suggestion and here is the eighth core guideline. Please comment with any corrections as I am still learning this new system. 🙂

When recording student scores into a grade book, the teacher discovers that these are Johnny’s scores: 91, 91, 91, 91, 91, 70, 91, 91, 91, and 91. If the mean is used to calculate Johnny’s grade, the final grade would be 88.9% (B+). However, is this really an accurate representation of Johnny’s overall achievement? What caused the one abnormal score? Would not an A- be a more accurate reflection of Johnny’s grade?

I use categories when grading, and when I have more than ten assignments in a category I sometimes drop the lowest score. If a student just had a rough day or for whatever reason had one score outside of the normal range, I think it’s fair to drop one score. However, if I allow retakes of tests or other major assignments, I do not drop a low score.

I joked at our meeting the other day that maybe grading should use Olympic scoring where the top and bottom score is dropped with the middle scores measuring achievement. The extreme scores would not factor into the final average.

Regardless, is it acceptable to ignore the mean when grading? Should other factors determine final grades?