A common question I hear from school and district leaders implementing standards-based grading is deceptively simple:
Should we use a 3-point scale or a 4-point scale?
Often, this question emerges after professional learning experiences or deeper conversations about grading philosophy. Educators that have already moved away (or will soon be moving away) from percentages begin to wonder whether fewer performance categories might better serve students.
What Does the Research Say?
To be clear at the outset:
I’m not aware of any empirical research that explicitly argues for a 3-point scale over a 4-point scale (or vice versa).
That said, there is a body of writing that cautions educators against assuming that more categories automatically lead to greater precision (See: “The Case Against Percentage Grades” by Thomas Guskey). This argument most often appears in the context of moving away from percentage-based grading systems and toward standards-based approaches that use a distinct number of clearly defined performance levels, typically somewhere between 2 and 7 categories.
The Illusion of Precision
Drs. Thomas Guskey and Susan Brookhart address this misconception directly in their work on grading and reporting. They note that many educators equate the number of categories on a grading scale with accuracy:
“Many educators assume that because the percentage grading scale has 100 classification levels—or categories—it is more precise than a scale with just a few levels (such as excellent, satisfactory, and poor). But in the absence of a truly accurate measuring device, adding more gradations to the measurement scale offers only the allure of precision…
When well constructed, grading scales with fewer categories that describe clearly distinct levels of student mastery or proficiency are not only more reliable, but also offer students better information to guide improvements” (pp. 219–220).
This idea, the allure of precision, is especially important in standards-based grading conversations. If educators cannot consistently distinguish between adjacent performance levels, then adding more categories may actually reduce reliability rather than improve it.
So…3 Points or 4 Points?
Rather than asking which number is better, a more productive set of questions might be:
- Can teachers consistently and confidently distinguish between each performance level?
- Are the descriptors for each level clear, instructionally meaningful, and student-friendly?
- Does the scale support actionable feedback rather than point accumulation?
- Does the scale align with how the district wants teachers and students to talk about learning?
Answering these questions can assist a school or district determine the number of performance levels that are consistently understood and therefore, defensible.
The Big Takeaway: Shared Understanding and Consistency
The most important decision is not whether a grading scale has three or four levels. The real work lies in:
- Developing shared understanding of what each level represents
- Ensuring consistency of interpretation across classrooms and schools
When grading systems are thoughtfully designed with clearly distinct performance categories, fewer levels can often lead to greater clarity, reliability, and feedback.
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(This article was originally written for the Iowa Association for Learning, Teaching and Leading’s “The Source” e-newsletter)
Disclosure: The ideas originate from the author. Generative AI was used to proofread and revise this blog post for clarity.