Your overall grade might have dropped even after you received a perfect score of 100% on an assignment because of how gradebooks calculate averages, especially when weighted categories are involved and new assignments are introduced. This often happens because, before a grade for an assessment is entered, its specific weighting value is not yet factored into your overall average.
When that 100% score is finally entered, the weighting for that assignment, and potentially its entire category, becomes active in the calculation. If other assignments within that newly activated category are missing or have not yet been graded (and thus might be implicitly treated as zeros or not yet contributing positive points), the introduction of that category's full weight, even with your 100% score, can dilute your previously higher average, which might have been based on fewer, high-performing assignments from other categories.
Understanding Weighted Grade Calculations
Most gradebooks use a weighted average system, where different assignments or categories (like quizzes, homework, or exams) contribute a specific percentage to your final grade.
- Before a Grade is Entered: Imagine a significant portion of your course grade (e.g., "Projects," worth 40%) has no grades entered yet. In many gradebook systems, this 40% weight might not be actively pulling your grade down because there's nothing to calculate for it. Your current grade is effectively being calculated only based on the graded portions of the course. If you had a perfect 100% average on all other assignments completed so far, your displayed grade could be 100%.
- When a 100% Grade is Entered: When you submit a project and score 100%, the gradebook now begins to factor in the "Projects" category's 40% weight. If this category includes multiple projects, and only the one you got 100% on is entered, while others are still missing (and perhaps implicitly count as zeros or just haven't been factored in yet), the overall effect can be a drop. Your 100% on one project might be averaged with 0% for unsubmitted projects within that 40% category, bringing down the category's average, and subsequently, your overall course average.
How a Perfect Score Can Lower Your Average
Let's illustrate with an example:
Consider a course with two main categories:
- Quizzes: 30% of your overall grade
- Projects: 70% of your overall grade
And assume the "Projects" category contains two projects, each worth 35% of the overall grade.
| Category | Weight (of Total Grade) | Assignment | Your Score | Before New Score | After New Score |
|---|---|---|---|---|---|
| Quizzes | 30% | Quiz 1 | 100% | 100% | 100% |
| Projects | 70% | Project 1 | (Not Graded) | N/A | 100% |
| Project 2 | (Not Graded) | N/A | Missing (0%) |
Scenario:
-
Initial State (Before Project 1 is Graded):
- You have a perfect 100% on Quiz 1. Since no project grades are in, the 70% "Projects" weight is effectively inactive in the calculation.
- Your gradebook calculates your current average as 100% (based purely on the 30% of the course that has been graded).
- Calculation: (100% * 0.30) / 0.30 = 100%
-
New State (After Project 1 is Graded 100%):
- You get 100% on Project 1.
- Now, the 70% weight for "Projects" becomes active. However, Project 2 is still missing or not yet graded, and some systems might count missing assignments as a 0% once the category is active.
- Project Category Average: (100% [Project 1] + 0% [Project 2]) / 2 = 50%
- New Overall Grade:
- (100% 0.30 [Quizzes]) + (50% 0.70 [Projects])
- = 30 + 35
- = 65%
- Your overall grade has dropped from 100% to 65%, even though you got a 100% on Project 1!
What to Do
If you see your grade drop after a perfect score, it's usually not an error in the gradebook. It's a reflection of how the overall course weight is being distributed and calculated as more assignments become active:
- Check Gradebook Details: Always review the full gradebook breakdown. Look at category weights, individual assignment weights, and how missing assignments are being treated. Reputable gradebook documentation often explains these calculation methods in detail.
- Monitor Missing Assignments: Ensure all assignments are submitted and graded. Missing assignments, particularly in weighted categories, can significantly impact your average even when you excel in other areas.
- Communicate with Instructor: If you're unsure or concerned, speak with your instructor. They can clarify how grades are weighted and calculated for their specific course.
