Posted by Orin Kerr:
The Inevitabillity of Grading Curves:
http://volokh.com/archives/archive_2007_09_30-2007_10_06.shtml#1191535566
In the comment thread to my post on the lawsuit over grading curves,
commenter [1]"Eli Rabett" writes:
It is not the job of a university to rank its students, it is the
job of a university to educate them. If a student masters the work
at an A or B level, and then gets knocked down to a C by curving,
something is very wrong with the ethics of the teacher.
I think this reflects a very basic misunderstanding about grading,
so I thought I would offer some thoughts in response.
The reality is that all grading is curved. The only differences are
among grading on curves that are more or less explicit and more or
less strict. Consider what it means to have "A level mastery" of a
subject. What does that mean? There is no intrinsic meaning to an "A"
level of mastery, or a "B" level, or a "C" level. Rather, these are
relative levels of mastery based on expectations for what level of
performance is acceptable or appropriate at different levels of
education. The concept is inherently relative.
To see this, imagine you are a teacher and you are grading papers
analyzing George Orwell's Animal Farm. You pick up and read a paper,
and it reveals the level of insight and understanding you might expect
from a 10th grader. What grade does it deserve? I think the answer
depends on entirely where you are. If you are a 6th grade English
teacher grading the work of 6th graders, then the paper deserves an A;
if you are an English professor teaching English graduate Ph.D.
students, the same paper deserves an F. The paper is the same either
way. It's just that we have a natural sense of scale -- of a curve --
for what level of insight and sophistication is to be expected at
different levels of educational achievement.
Some grading schemes hide these judgments by relying on numbers. A
score might be a 86.5 out of 100, or a 91.8 out of 100. Aren't these
grades absolute rather than curved, with the first grade being an
objective "B" and the later an objective "A-"? The answer is no. The
common convention that an "A" range grade is a 90-100, a "B" range
grade is 80-89, etc. is also just a curve; it's a common curve, but a
curve nonetheless. It works on the premise that the professor who
writes an exam uses a relative distribution of easy and difficult
problems so that the scores will track the class's expected levels of
achievement.
That is, the teacher will aim for a specific mix of easy, medium,
and hard questions so that the likely mix of answers will produce
something like the desired distribution of percentage correct answers
and then converted into the desired distribution of letter grades. If
the questions are too easy you get too many A's, and if they're too
hard you get too many C's; the teacher aims for the right mix to get
the right distrubution. This is also a curve, but students usually
don't think about that because it's "hidden" in the level of
difficulty of the question.
Controversy over the use of curves usually comes where curves are
strict and explicit, imposing a specific distribution of grades in a
class ex post rather than quietly aiming for that ex ante. This has
the effect of making students much more aware of curves, heightening
the sense that there is a clear difference between a "true" grade and
a "curved" grade. The arguments for or against a strict curve are a
lot like the debates over rules versus standards; there's a choice
between giving professors more or less judgment about the relative
performance of the class, and there are pros and cons to both
approaches. But the choice in that setting concerns how classes are
curved, not whether they are curved; whether students realize it or
not, all grades are curved.
References
1. http://volokh.com/posts/1191515333.shtml#276489
_______________________________________________
Volokh mailing list
[email protected]
http://lists.powerblogs.com/cgi-bin/mailman/listinfo/volokh
