How Does a Grading Curve Work?

Video Transcript

"There's two kinds of grading curves that a teacher might use. The first kind of grading curve is where they take the span of grades and they'll take the highest grade. Let's say the highest grade is 92, so they'll take the highest grade which is 92 and then they'll say that's now a perfect score, so they'll add 8 points because 92 is 8 points shy of a 100 which would have been a perfect score, they'll add eight points on to every other score. So essentially they'll take the whole span of scores and say, since the highest was 92 we're going to treat that as a hundred and move everybody's grade up 8 points, so this 92 plus 8 literally does become a 100. Somebody else maybe who had gotten an 84 with the curve now has a 92, so a 84 curve on this curve, on this grading curve will be a 92. That the first kind of grading curve. I think it's the one we see most often, especially in high school and in lower grades. The second kind of grading curve is a distribution curve, where a teacher maybe even before the class starts, before the semester starts says, there's going to be a certain amount of A's, B's, C's, D's and F's, and we're going to distribute those grades across this, we're going to have 15 percent A's and a certain percentage of B's, D's and 5 percent F's, and that will be called a distribution curve. And then as the test come in and as the grades come in through the semester the professor or the teacher would actually change the grades to fit that distribution. So let's say he had said they'll be 15 out of a hundred students in the class should get an A, whatever the top 15 grades were in this span of grades, in this list of grades, whatever the top 15 grades were, even if they'd all been C's will now be A's, so it doesn't matter what percentage they got right, those top 15 scores will now be A's, the bottom 5 scores will all be F's. That's a much less common grading curve I think, I think we see this kind more often. Although I've heard in university we see the distribution sometimes, and that will be called the distribution grading curve."