How to create a grade curve

What is a Grade Curve?
A grade curve, also known as grading on a curve, is a statistical method of adjusting scores to match a predetermined distribution. It means that the grade is relative to how well everyone else in the class performed. In other words, it compares students’ performance to their peers rather than to a set standard.

Why Use a Grade Curve?
The primary reason that teachers use a grade curve is to account for variations in the difficulty of a test or assignment. For instance, if a test was much more challenging than expected and many students didn’t perform well, factoring in a grade curve could help adjust the grades to match the class’s distribution more accurately. Also, it’s a great way to reward students who surpass the expectations of their peers.

How to Create a Grade Curve
Creating a grade curve requires some math skills and a bit of work, but it’s not challenging if you follow the steps below.

1. Define The Grade Distribution: Before you can grade on a curve, you need to define how you want your grade distribution to look like. The most commonly used distribution is a bell curve. You can decide the percentage of students who will receive each grade (e.g., A, B, C, or D). For instance, you can use the below distribution:

A: 20%
B: 30%
C: 40%
D: 10%

2. Calculate The Average, Standard Deviation, and Range: Once you’ve defined your grade distribution, you need to calculate the average, standard deviation, and range of scores. This information will give you an understanding of how your students performed in the exam or assignment and their variations.

Average: (Total of all student’s scores) / (Number of students)
Standard Deviation: (Sum of all (score – average)^2) / (Number of students)
Range: (Highest Score – Lowest Score)

3. Determine The Cutoff Points: These are the points on the distribution where students will receive a grade. You can do this by calculating the percentage of students who will fall into each grade category in line with your chosen grade distribution.

4. Apply The Grade Curve: Once you have all your data in the right order, you can now apply the curve. Here you’ll shift the grades to match your desired grade distribution. You can do this by adding or subtracting points from the student’s scores that are below or above the average. You may also choose to adjust the breakpoint to raise grades if the variation turns out to be too low.

Conclusion
While creating a grade curve takes a bit of time and effort, it’s an excellent way to promote fairness and equity among your students. It’s essential to be transparent with your students about how you intend to grade their performance on a curve. Remember, grading on a curve relies on a performance comparison to others, so make it crystal clear how your students’ understanding of grading on a scale compares to this methodology. Ultimately, they will appreciate the effort taken to make grading as fair as possible.