Curving Grades: How do teachers do it?

Hey guys, I've always wondered how teachers curve grades in their classes. What are some common methods they use to adjust the grades of students? Does it vary between teachers or is there a standard way?

Hey there! Curving grades is a method used by teachers to adjust students' raw scores to better reflect the intended distribution of grades. There's no one-size-fits-all approach, but there are some common methods that teachers might use to curve grades. Here are a few examples:

1. Linear curve: This is the simplest form of curving, where the teacher adds a constant number of points to every student's score. For example, if the highest score in the class is 80%, the teacher might add 20 points to everyone's score to make the highest score 100%.

2. Bell curve (normal distribution): In this method, the teacher adjusts the grades to fit a bell curve, with the majority of students receiving average grades and fewer students receiving high or low grades. This can be accomplished by using a mathematical formula or by determining the average and standard deviation of the class, then reassigning grades based on their position in relation to the average.

3. Square root method: This involves taking the square root of each student's raw score and multiplying it by a constant factor (often 10) to determine the curved score. For example, if a student initially scored 70%, their curved score would be sqrt(70) x 10 = 83.67%. This method tends to benefit students who scored lower on the original scale.

4. Clipping: This method adjusts the maximum and/or minimum possible scores, effectively "clipping" outliers. For example, if the highest grade in the class is 80% and the teacher decides that the top grade should be 90%, they would raise every student's grade proportionately. Any grade above 90% would be clipped to 90%.

5. Sliding scale: In this approach, the teacher curves the grades based on an adjustable sliding scale. If the class average is below a set threshold, the sliding scale will be adjusted such that the new average is higher. This can be done by re-assigning the grades based on a different scaling criterion or by introducing a more lenient curve.

Keep in mind that the method a teacher uses to curve grades can vary significantly depending on their individual preferences and what they think is best for their students. Some teachers may not curve grades at all, or they might use a combination of these methods. Ultimately, it's up to the teacher to decide which method works best for their class and supports a fair assessment of students' learning.