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Turning A Four-Point Rubric Score into A Letter Grade: How Can This Be Done?

by Eileen Depka

The answer is…carefully! When using a four-point rubric, such as the one below, a score of three is typically a score that shows students are achieving at an acceptable level. After all, it is the second highest point value on the rubric. Teachers who need to use letter grades are in a bind. Often the easiest way is to take the score earned on the rubric and turn it into a percentage. Mathematically this is accomplished by dividing the points earned by the number of points possible. This method alone will not give an accurate picture of student achievement. When earning three points on a four-point rubric, a student has performed well. Three out of four points mathematically, though, is only a score of 75 percent. In many grading systems, the student is now left with an undeserved D.

To be fair to students and to calculate a more accurate reflection of student performance, the numbers can be manipulated slightly to achieve a grade that is more indicative of the quality of the product.

SOLVING EQUATIONS - GRADING RUBRIC

Name   Suzie Sample         Date   Today  

Criteria 1 2 3 4
Equation solution Answer only is shown Initial equation and answer only are shown Initial equation, steps, and answer are shown Initial equation, all steps, and answer are shown
Equation answer Answer is incorrect Steps are incorrect or not present, but answer is correct Steps are correct, but answer is incorrect Steps are correct and answer is correct
Explanation of solution Explanation is present but demonstrates a lack of understanding Explanation indicates a minimal understanding of procedure Explanation indicates procedures are understood Explanation clearly indicates procedures are understood at an advanced level

Points possible = 12       Points earned = 10

This student would receive 83 percent as a result of her rubric score if the evaluator changes it into a percent. If that is the desired method, try using one of the options below to determine the letter grade. It might give a fairer picture of achievement.

Option One:

Turn the rubric score into a percent by dividing the points earned by the points possible, and then use the scale provided.

Example: Student earns 10 out of 12 points. 10 ÷ 12 = 83%, 83% = B

88 – 100 = A
75 – 87 = B
62 – 74 = C
50 – 61 = D
0 – 50 = F
This is a suggested point scale that seems to work fairly well. Percents can be adjusted up or down to best meet the needs of students.

Option Two:

Determine the total points possible for the rubric. Divide the total possible by 5 to determine the increments for each point group. This is done because there are 5 grades in the A, B, C, D, F grading scale.

Example: rubric points possible total = 12, 12 ÷ 5 = 2.4

The (quotient) answer determines the highest point value for the F group. F = 0–2.4 points
To determine the highest value for the D group add the quotient (answer) to the highest point value in the F group. D = 2.41–4.8 points
To determine the highest value for the C group add the quotient (answer) to the highest point value in the D group. C = 4.81–7.2 points
To determine the highest value for the B group add the quotient (answer) to the highest point value in the C group. B = 7.21–9.6 points
To determine the highest value for the A group add the quotient (answer) to the highest point value in the B group A = 9.61–12 points

Option Three:

Determine the points earned and divide by the number of categories scored in the rubric. The answer will be a number between 1 and 4 when the rubric has a 1–4 point scale.

Example: 4-point rubric with 3 categories graded within. Student scores 10 points. 10 ÷ 3 = 3.33, 3.33 = B

1–4 Rubric Scale no zero used

A = 3.41–4.0
B = 2.81–3.4
C = 2.21–2.8
D = 1.61–2.2
F = 1.0–1.6
1–4 Rubric Scale with optional use of zero for no evidence of a performance

A = 3.21–4.0
B = 2.41–3.2
C = 1.61–2.4
D = 0.81–1.6
F = 0.0–0.8
0–3 Rubric scale

A = 2.41–3.0
B = 1.81–2.4
C = 1.21–1.8
D = 0.61–1.2
F = 0.0–0.6

Each of the options provided aims to change a four-point rubric scale into a five-point letter grade scale. The result of using any of the three provided will be a more realistic picture of student achievement.