A grade curve is a relative grading procedure that assigns a score for a given assignment based on the performance of the class taken as a whole. There are many reasons why a teacher or professor may decide to draw a grade curve. For example, it can do this if the majority of students perform below expectations, which implies that the test or assignment was out of range in terms of scope and difficulty. Some methods of making a curve adjust grades mathematically, while others provide students with the opportunity to recover lost points on an assignment. Read on for details.
Steps
Method 1 of 2: Plot the Grade Curve with a Mathematical Method
Step 1. Mark the highest grade as "100%" of the performance
It is one of the most common, if not the most common, of the methods that teachers and professors use to draw the curve. With this method, the teacher searches for the highest grade in the class and marks it as "new" 100% for that particular assignment. This means that you will have to subtract the highest score in the class from the hypothetical "perfect" score, then add the difference to each assignment, including that of the highest score. If done correctly, the highest scoring task will now have a perfect score, and the other tasks will have a higher score than before.
- For example, if the highest score for a test was 95%, since 100-95 = 5, we should add "5 percentage points" to all students' scores. This will make 95% a 100% settled, and increase every other score by 5 percentage points.
- This method also works with absolute scores, as well as with percentages. If the highest score was 28 out of 30, for example, you will need to add 2 points to the score for each assignment.
Step 2. Implement a graduated scale curve
This technique is among the simplest methods for using a grade curve. It is used when there is a particular difficulty on a specific section of a task, which the overwhelming majority of the class has solved badly. To draw the curve according to a graduated scale, simply add the same number of points to each student's grade. It may be the number of points that everyone has been given to the wrong exercise, or it may be an arbitrary amount of points, which seems adequate to you.
- For example, suppose the entire class missed an exercise worth 10 points. In this case, you can choose to add 10 points to each student's score. If you think the class doesn't deserve the highest credit for doing that exercise wrong, you can choose to give 5 points instead of 10.
- This method is closely related to the previous method, but it is not the same. The latter does not specifically consider the highest score in the class to be "100%". It may therefore happen that no one receives the "perfect" grade, just as it may happen that there are scores higher than 100%!
Step 3. Mark a limit on the shortcomings
This method mitigates the effect that a few very low grades can have on the grade of the class. It is therefore used in situations where a student (or an entire class) has failed in a certain task, but has still shown remarkable progress from the start and does not deserve to be penalized. In this case, instead of a normal percentage scale assigned to grades (90% for A, 80% for B, up to 50-0% for F), define a limit to negative grades, a minimum score greater than zero. This allows tasks with a particularly low score to have a less drastic effect when combined with the average of a good student. In other words, a bad grade will affect a student's overall average less.
- For example, suppose a student completely fails their first test, achieving a 0. Since then, however, the student works hard and receives 70% and 80% in his next two tests. Without a curve it will have an average of 50%, therefore a negative score. But if you put a limit on negative scores at 40%, then his new average will be 63.3%, which is a D. It is not an extraordinary grade, but it is fairer than a completely negative grade for a student who has shown commitment.
- You can choose to limit different negative grades, based on the difference between a submitted and an undelivered assignment. For example, you can decide that undelivered assignments have a minimum grade of 40%, but if delivered they will have a minimum grade of 30%.
Step 4. Use a bell curve
Often, the grades of a given assignment are distributed in a kind of bell. Few students get high grades, many get average grades, few students get bad grades. What would happen if, for example, in a particularly difficult task, the few high marks were in the range of 80%, the average marks in 60% and the negative marks in 40%? Do the best students in your class deserve less than a B and the average students less than a D? Probably not. With a bell curve, you mark the average grade of the class with a C, which means that the best student will receive an A and the worst an F, beyond their overall grades.
- Start by determining the average class score. Add up all the grades in the class and divide by the number of students to find the average. Let's imagine that we find an average score of 66%.
- Mark this as an average score. The precise score to use is at your discretion. It can be a C, a C + or a B-, for example. Let's imagine scoring 66% with a nice round C round.
- Then decide how many points to separate each letter on the bell curve. Generally, the larger the interval, the more likely the bell will tend to "forgive" students with negative grades. Let's imagine that one vote is separated from the other by 12 points. This means that the new B will be 66 + 12, i.e. 78, while 66-12 = 54 will be the new D.
- It thus assigns grades based on the bell curve.
Step 5. Apply a linear scale grading curve
When you have a specific idea of the distribution you want to achieve, but the actual grades are not adequate, you can use a linear scale curve. This curve allows you to adjust the distribution of the marks so as to consider the position of the average score exactly where you think it is adequate. However, it is very technical and uses a different grade curve for each student, which can be perceived as unfair.
- First, choose 2 base scores (scores received by students) and determine how much they should match in the curve. For example, let's say the task average is 70% and you want it to reach 75%, while the lowest score is 40% and you want it to be 50%.
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Next, create 2 x / y points: (x1, y1) and (x2, y2). Each X value will be one of the absolute scores chosen above, while each Y value will correspond to the final value you want the X to reach. In our case the points are (70, 75) and (40, 50).
- Enter the values in the following equation: f (x) = y1 + ((y2-y1) / (x2-x1)) (x-x1). Note only the X without exponents, insert it in the score of each individual task. The final value you will get for f (x) is the new grade of the assignment. You will obviously have to run the equation for each student's grade.
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In our case, let's imagine we want to create the curve of a task that has an average of 80%. We will solve the equation as follows:
- f (x) = 75 + (((50 - 75) / (40-70)) (80-70))
- f (x) = 75 + (((-25) / (- 30)) (10))
- f (x) = 75 +.83 (10)
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f (x) = 83.3. The score of 80% for this task became 83, 3%.
Method 2 of 2: Give Students Additional Help
Curve Grades Step 6 Step 1. Offer the opportunity to redo an assignment
If you're not interested in applying a complicated formula to your students' grades, but still want to give them the opportunity to improve their score, consider reassigning sections of the assignment that failed. Give the students the assignment back and allow them to redo the unsolved problems. Then, rate the remade exercises. Give students a percentage of the points they have earned from the new attempt, and add it to the first score to get the final score.
- Let's say a student scored 60 out of 100 on a test. Redistribute the test to the student, offering half the credit for each solved exercise. The student will solve the problems by getting another 30 points. You will then give 30/2 = 15 points more, which, added to the initial 60, will give you a final score of 75 points.
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Avoid having students just correct their work. Instead, try to make them fully understand the method of solving problems, from start to finish, completely rewriting the wrong parts.
Curve Grades Step 7 Step 2. Remove a section of an assignment and give grades back
Even the best teachers are sometimes unfair or misleading when testing. If, after grading, you find that there is a part, or parts, of the assignment that is particularly difficult for students, you can skip that section and graduate again as if it never existed. It's a great idea if some questions are based on concepts you haven't taught your students yet, or if the question objectively goes beyond your expectations of class performance. In these cases, redistribute the votes as if that section didn't exist.
Note, however, that this method gives more weight to the questions you choose to include. It may anger students who answer well to the questions you choose to eliminate. You could offer them some form of additional credit
Curve Grades Step 8 Step 3. Assign problems that give extra credit
This is one of the older tricks. After an assignment that has gone wrong for some or all students, offer them a special problem, project, or specific assignment which, when completed correctly, will increase their score. This can be a problem that requires creative skill, an original assignment, or a presentation. Be creative!
