If you have an activity that uses ratings, for example forum or glossary, and you set the rating aggregation to "count" the student's grade should be the number of ratings they have received. If you set the ratings to also use a custom scale an item from this scale will be output on the grader report. For example if your scale is "bad, meh, good" and the student receives one rating their grade should be 1. Instead their grade is displayed as "meh" which happens to be the scale item at index 1.