In order to come to a conclusion, you really have to consider why a four-point mastery scale is so different from a traditional grading scale. With a traditional grading scale, most schools assume that:
A means “Excellent”
B means “Good”
C means “Average”
D means “Below Average”
F means “Failing”
There are several big problems with this scale. It attempts to associated a single letter-grade with a single descriptive statement.
Fair enough, but what does a C really mean in your class? In order to paint a thin veneer of numerical gravitas onto our letter grades, we place numerical cutoffs on them. For example, earning 70% of the total possible points in a class will result in an C, yet how these points are earned varies from teacher to teacher and subject to subject. Outside of a course that adheres to the dreaded bell-curve, a “C” almost never reflects anything close to average performance. In fact, I find “C” to be a really interesting grade, because there are so many ways to earn it. You could get C’s on every test and assignment and earn a C on your report card. You could also get A’s on your tests but fail to turn in any of your assignments and get a C on your report card. Finally, you may score D’s and F’s on all of your exams but turn in every assignment along with some of that magical extra-credit and get a C on your report card. That’s three very, very different ways to earn the same letter grade yet report cards make no effort to explain the difference.
The problem here isn’t about letters, numbers, and percentages. It’s really about what grades have come to represent in our educational culture. Traditionally, the only thing our grading system truly tells us about students is how many points they managed to earn during the course of the semester. Every other conclusion we draw from traditional grades is highly suspect. The advantage of using a mastery-scale is that there is far less room for individual interpretation of the scores. Mastery-level grades imply the following:
Level 4: The student is able to show understanding of a concept or perform a skill that is more complex than what was explicitly taught in class.
Level 3: The student is able to show understanding of a concept or correctly perform a skill that has been explicitly taught in class.
Level 2: The student is able to show basic understanding of a concept or correctly perform a skill at a basic level. More complex skills and concepts require assistance from the teacher.
Level 1: The student shows no understanding of the concept, nor can the student correctly perform the skill at a basic level without considerable help from the instructor.
These scores are very specific about what the student has proven they understand or shown that they can do. This does not mean that such a system is perfect. You need a clear and concise list of learning goals before you can start grading on such a scale, and you also need a very good set of assessments in order to produce scores that truly indicate student achievement. In the end, however, you may be surprised at how simply changing the way you assign grades to your students transforms everything else about your classroom and your instruction. In my own experience, the changes have been profoundly positive for nearly all of my students.