How to Curve Values: 8 Steps (with Pictures)

2024 Author: Jason Gerald | [email protected]. Last modified: 2024-02-01 14:11

A grade curve is a relative grading procedure that determines the assignment of grades to assignments based on students' overall grades in the class. There are many reasons why a teacher or lecturer might decide to curve grades - for example, if most students score below the expected standard, that might indicate that the assignment or test is outside the scope of the material or a reasonable level of difficulty. Some curve methods adjust grades based on mathematical calculations, while other methods give students the opportunity to regain some of their lost points on an assignment. Keep reading for more detailed instructions.

Step

Method 1 of 2: Curving Values Based on Mathematical Calculations

Step 1. Set “100%” as the highest value

This is one of the most common (if not the most common) methods used by teachers and lecturers to curve grades. This curve method requires the teacher to find the highest grade in the class and assign that grade as the new “100%” grade for the assignment. This means that you take the highest grade in the class from a hypothetical “perfect” score, then add the difference to each assignment, including the one with the highest score. If done correctly, the task with the highest score will now have a perfect score and every other task will get a higher score than before.

For example, let's say the highest score on a test is 95%. In this case, since 100-95 = 5, we will add 5 percent points on each student's grades. This will make the 95% score 100% and every other score 5% higher than before.
This method can also be done using absolute scores, rather than percentages. If the highest score is 28/30, for example, you will add 2 points to the score for each task.

Step 2. Use a flat-scale curve

This technique is one of the simplest methods used to curve values. This technique is especially useful when there is a particularly difficult question on an assignment that most students cannot answer in class. To curve grades based on a flat-scale curve, simply add the same number of points to each student's grade. This can be the number of points on one question that most students in the class cannot answer, or it can be another number of points (by mutual agreement) that you think is fair.

For example, let's say that all the students in the class cannot answer a question that is worth 10 points. In this case, you can choose to add 10 points to each student's score. If you think students don't deserve full points for the questions they can't answer, you can also choose to add only 5 points.
This method is very similar to the previous method, but not quite the same. Since this method does not specifically specify that the highest score in the class as the maximum score of 100%, it allows for the possibility that “none” of the assignments gets a perfect score. This method even allows scores above 100%!

Step 3. Determine the lower bound for the value of F

This curve method eliminates the adverse effect that some very low scores have on a student's grades. Therefore, this method is especially useful in situations where a student (or all students in the class) did poorly on an assignment but has since shown significant improvement, and, in your opinion, deserves not to fail. In this case, instead of using normal percentage assessments for letter grades (90% for A grades, 80% for B grades, etc. to 50-0% for F grades), you set a lower limit for failed grades - the minimum grade that higher than zero. This keeps assignments that get bad grades from having a drastic effect when averaged against the student's good grades. In other words, a few bad grades did not significantly lower a student's overall grade.

For example, let's say a student completely failed his first test, with a score of 0. However, since then, he has been studying very hard, and has scored 70% and 80% on the next two tests. Without the curve, he has a current value of 50% - a failing grade. If we set a lower threshold for failing grades of 40%, the student's new average becomes 63.3% - a D. This is not a “great” grade, but it may be fairer than failing a student who has shown progress. means.
You can choose to set a lower limit for submitted tasks versus uncollected tasks. For example, you may decide that, for failed assignments, the lowest possible score is 40%, unless the assignment is not submitted at all, in which case 30% is the lowest possible score.

Step 4. Use the bell curve

Oftentimes, the range of grades on a given assignment is distributed in a form that resembles a bell curve - a few students get high marks, most students get moderate scores, and a few students get low scores. What if, for example, on a very difficult task, high grades are in the 80% range, medium grades are in the 60% range, and low grades are in the 40% range? Do the best students in your class deserve a low B and most students deserve a low D? Probably not. Using the bell curve grading method, you determine your class average as a middle C, meaning that your best students will get A's, and your worst students will get F's, regardless of their absolute score.

Start by determining the class mean (average). Add up all the grades in the class, then divide by the number of students present to determine the class average. For example, after doing this, we find that the class average is 66%.
Define this value as the mid-range value. The exact value you use is at your discretion - you may want to specify the mean as a C, C+, or even B-, for example. For example, let's say we want to define the mean of 66% as a rounded C value.
Next, determine how many points separate the letter values in your new bell curve. Generally, a larger point interval means your bell curve is more welcoming to low-scoring students. Let's say, in our bell curve, we want to separate our values by 12 points. This means that 66+12 = 78 becomes our new B value, while 66 - 12 = 54 becomes our new D value, and so on.
Rate according to the new bell curve system.

Step 5. Use a linear scale grading curve

When you have a very specific idea about the distribution of values you want, but the actual values in your class don't match, you may want to use a linear scale curve. This curve allows you to adjust the distribution of values to get the average value exactly the way you want it. However, this method also requires intensive mathematical calculations and technically uses a different scoring curve for each student, which some may find unfair.

First, choose 2 raw grades (actual student grades) and decide how much you want them to be after the curve. For example, let's say the average grade for an assignment is 70% and you want the average to be 75%, while the lowest grade is 40% and you want the lowest grade to be 50%.
Next, make 2 points x/y: (x₁, y₁) and (x₂, y₂). Each x-value is one of the raw values you choose, while each y-value is the resultant value of curving the raw value you “wanted.” In our example, our points are (70, 75) and (40, 50).
Plug your values into this equation: f(x) = y₁ + ((y₂-y₁)/(x₂-x₁)) (x-x₁). Pay attention to the variable “x” which is without any digits - for this, enter the grade for each student's assignment. The final grade you get for f(x) is the assignment's new grade. To assert - you must use the equation for each student's grade.

In our example, let's say we curve an assignment that scores 80%. We will solve the above equation as follows:
- f(x) = 75 + (((50 - 75)/(40-70))(80-70))
- f(x) = 75 + (((-25)/(-30))(10))
- f(x) = 75 + 0, 83 (10)
- f(x) = 83, 3. The 80% score on the task is now 83, 3%.

Method 2 of 2: Providing Additional Help to Students

Step 1. Offer improvement opportunities

If you are not interested in using complex formulas on your students' grades, but you still want to offer them the opportunity to improve their grades on an assignment, consider offering students an opportunity to correct the parts of the assignment they didn't do well. well before. Return the assignment to the students and allow them to correct their incorrect answers. Then, rate the answers they have corrected. Offer students some percentage of the points they earn on their improvement efforts, and add these extra points to their first grade to get their final grade.

Let's say a student gets 60 points out of 100 points on a test. We return the test to him, offering him half marks for the questions he corrects. The student reworked the missed problem, and got an additional 30 points. We then give him 30/2 = 15 additional points, so the student's final score is 60 + 15 = 75 points.
Don't just ask students to correct their answers. Instead, to make sure they fully understand how to work on the questions from start to finish, have them rewrite their corrective answers in their entirety.

Step 2. Remove one question from the assignment and do a reassessment

Even the best teachers sometimes make unfair or incorrect questions on their tests. If, after doing the assessment, you find that there are one or two particular questions that seem difficult for most students, you can ignore those questions and grade the assignment as if they weren't there. This is a particularly good idea if a particular question uses a concept that you have not taught your students or if the question is beyond the reasonable demands of the student's ability. In these cases, re-evaluate the assignments as if the difficult questions did not exist.

However, it should be noted that this method puts an extra burden on the questions you choose to include in the assessment. It can also anger students who did well on the questions you chose to drop - you may want to offer students another form of extra grade

Step 3. Give extra questions for extra marks

This is one of the oldest tricks in the book. After an assignment has bad grades for some (or all) of your students, offer your students a special problem, project, or assignment that, if completed, will raise their grade. This could be an extra question that requires creative thinking, an extra assignment, or even a presentation - get creative!