Exams are a common form of assessing a student’s knowledge and understanding of a particular subject. While grading systems may vary across institutions and countries, one common practice used to adjust exam scores is called curving.
Curving an exam is adjusting grades to reflect the overall performance of students in the class. This is typically done when an exam is found to be more difficult than expected or if students perform poorly overall. Curving can also be used to balance out any biases or errors in the exam itself. In this article, we’ll dive into how exam curving works and the different types of curves that can be used.
How does exam curving work?
The process of curving an exam involves adjusting the raw scores of students by adding points to their original scores or by multiplying them by a factor. The goal is to bring the grades closer together to reflect the class’s overall performance. This process can be done in several ways:
Standard deviation curve
The most common method of curving is the standard deviation curve. In this method, the average score is determined, and then the standard deviation is calculated. The standard deviation measures the amount of variation in the scores. The more variation, the wider the curve will be.
The standard deviation curve usually involves adding or subtracting a certain number of points from the average score based on the standard deviation. For example, a professor may decide to add one standard deviation to the average score to get the highest grade, subtract one standard deviation from the average score to get the lowest grade, and leave the average score as is.
Percentage curve
Another way to curve an exam is to adjust the percentage scores. In this method, the professor determines what percentage of the class should receive each grade (for example, 10% A’s, 20% B’s, 30% C’s, and so on). The professor then adjusts the percentage boundaries based on the actual scores of the class.
For example, if the highest score in the class is an 85, the professor may decide to make 85 the cutoff for an A, even if that percentage is higher than the original percentage boundary. This method ensures that students are graded based on their performance relative to the rest of the class, regardless of the exam’s difficulty.
Fixed point curve
A fixed point curve is a method where a predetermined number of points are added or subtracted from every student’s score. This method is typically used when the exam is found to be much more difficult than anticipated, and all students are likely to receive low grades.
For example, a professor may decide to add ten points to every student’s score. This method can be useful when the exam is heavily weighted, and the poor performance could significantly impact the student’s overall grade in the class.
Pros and Cons of Exam Curving
Curving an exam has both advantages and disadvantages. Some advantages include:
- It can adjust grades to reflect the overall performance of the class, regardless of the exam’s difficulty.
- It can balance out biases or errors in the exam itself.
- It can provide a fairer assessment of student performance.
However, there are also some disadvantages to curving:
- It can be subjective, as different professors may choose to curve in different ways.
- It can mask individual student performance, as the final grade is heavily influenced by the performance of others.
- It can lead to grade inflation, as students may receive higher grades than they would have received without the curve.
Conclusion
Curving an exam is a process of adjusting grades to reflect the overall performance of the class. There are several methods of curving, including the standard deviation curve, percentage curve, and fixed point curve. While curving an exam has its advantages, it is important to be aware of the disadvantages and use discretion in its application.