Grading Numerology
I use percentages to map to letter grades.The percentages mirror the 4.0 scale, except that where a GPA difference of 1.0 corresponds to a full letter grade,I use a percentage difference of 10. The table below shows the conversion from numerical grades to letter grades.
Why I don't round grades
It is my practice not to round the numerical gradebefore mapping to letter grades by the table.This can be a sore point, so let me explain.For example, I use ≥90.00 as the transition from a B+ to an A-.This means that if your numerical grade is 89.9, I map it to a B+and not an A-. It can be heartbreaking to miss agrade boundary by -0.1, I know.But to round up, say, every numerical grade ≥89.50 to 90.00and map that to an A-, means that the transition from B+ to A-is actually 89.50, not 90.00. And that would mean that a grade of 89.4 would miss a grade boundary by -0.1. (It would also mean that me announcing the grade boundary of 90.00is not accurate.)No matter whatpoliciy is followed, some could miss a grade boundary by a hair.Even though there may be some psychological difference betweenthe two situations, I prefer to keep it straightforward byannouncing the sharp grade boundary and then following it strictly.I find it helps keeps the process more objective, and does not allowroom for subjective grade adjustments, which are almost always unfair.
Number → Letter Conversion | ||
Numerical Grade | Letter Grade | Equivalent on 4.0 scale |
≥ 97.5 | A+ | 4.0 |
≥ 92.5 | A | > 3.7 |
≥ 90.0 | A- | > 3.3 |
≥ 87.5 | B+ | > 3.0 |
≥ 82.5 | B | > 2.7 |
≥ 80.0 | B- | >2.3 |
≥ 77.5 | C+ | > 2.0 |
≥ 72.5 | C | > 1.7 |
≥ 70.0 | C- | > 1.3 |
≥ 67.5 | D+ | > 1.0 |
≥ 62.5 | D | > 0.7 |
≥ 60.0 | D- | > 0.0 |
< 60.0 | E | 0.0 |
Letter → Number Conversion | |
Letter Grade | Numerical Grade |
A+ | 98.75 |
A | 95.00 |
A- | 91.25 |
B+ | 88.75 |
B | 85.00 |
B- | 81.25 |
C+ | 78.75 |
C | 75.00 |
C- | 71.25 |
D+ | 68.75 |
D | 65.00 |
D- | 61.25 |
E | 55.00 |
