Scales are a useful tool for teachers that let you give more refined automatic feedback. With scales, you can assign names to numerical grade values, allowing you to set up systems like:

• The Cool Scale - Not cool, Not very cool, Fairly cool, Cool, Very Cool, Super Cool
  • Each increment could be worth 1, 2, 3, 4, 5 and 6 points respectively in a Sum (aggregations like Natural) aggregation method, or from 0/5 to 5/5 in a Normalized (aggregations like weighted and simple weighted mean of grades) method.
    • Different reports may show differently. By default gradebooks are set to Natural aggregation which is the recommended aggregation type for easy gradebook setup.
• Complete/Incomplete- a two-point scale
  • In a Normalized aggregation method it would be 1/1 and 0/1 respectively
  • In a Sum aggregation method it would be 1 and 2 respectively

The aggregation method used with Scales affects scores. While you and your students will see the values assigned by a grading scale in the Grader report and User report, these values will function numerically in grade book calculations depending on the kind of grade calculation being used.

For more info, see the MoodleDocs article on scales.