Eric Bohlman wrote (in part):
> It [the "budget assumption" in grading by quantiles]
> implies at least two questionable, to say the least, underlying
assumptions:
>
> 1) That the "total" of whatever it is that grades are supposed to measure
> is a constant depending only on class size.
>
> 2) That it's possible to evaluate the collective performance of a group
> on a task *before* they've performed that task.
Another possibility is that the grader has more faith in every class
being a random sample from the same population than in their own ability to
objectively grade their students.
When I started teaching I would have considered the random sample model
a reasonable approximation to the truth. Observation of classes over the
years has led me to conclude that the makeup of a class is less due to
random sampling than to Things Ye Wot Not Of. Sex ratios, age profile, etc.
all swing wildly from year to year; rarely do I have any idea why, despite
considerable curiosity.
-Robert Dawson
