[rayiner]

> If 40% of a class genuinely does exceptional work, 20% get mislabeled as mediocre. If it's a weak year and only 5% are truly exceptional, 15% get a free ride.

Having been on the grading side of things, this essentially never happens. As soon as you have a pool large enough where it is mathematically sound to have a curve (30 people or so), you will not find a situation where 40% do excellent work.

Coursework follows Sturgeon’s law. In a class of 30, there’s maybe 3-4 people who do excellent work, and there is a rapid fall off from there.

[pmyteh]

Agreed, but there are differences between different classes too: the students vary somewhat in intrinsic quality and motivation, and in those years I've done a particularly good job of teaching and motivation the results can be better overall because the students are putting more effort in.

Similarly the other way. There are classes I've given no first class (~A) marks in, because nobody earned one. Still a curve in practice, but with the top at an upper second.