University libraries often keep a file of old exams, at least for those
courses whose professors approve of the idea, and make them available to
students. As best I can tell, there are two reasons they do so. One is
to help students study for exams they are going to take. The other is
to prevent students who have access to old exams from other sources, a
friend who took the course the year before or a fraternity that keeps a
file of old exams provided by its members, from having an advantage over
students who lack such access. My own practice is to cut out the
middleman by webbing some of my old exams and linking to them on the
class web page.
I have, however, some reservations about the practice, having to do with
how the old exams are used by students. The way I want them to use the
exams is as a way of checking on how well they know the material, so
that if they think they understand part of it and don't they will
discover the problem before, not after, taking the final. My usual
suggestion is that, after studying, a student should take one of the
webbed exams and use my answers, if they are there, to check his. If the
answers are not there, he can at least go back to the book to see
whether what he wrote fits what it said.
What I do not want the student to do, and am concerned that many
students may try to do, is memorize the answers to all the question on
past exams on the theory that those are the questions that will appear
on the next exam. One problem with that is that you can memorize an
answer without understanding it. Another is that the exam questions,
even from multiple exams, cover only a fraction of what the students are
supposed to have learned; an exam is a sample of the course, not a
summary. If I limited my exams to questions from the old exams that I
have webbed, a student might be able to get a reasonable grade by
memorizing answers to those questions, but the grade would be poor
evidence of how much of the course he understood. Memorizing answers is
analogous to the practice of going through a textbook using a
highlighter to mark the five or ten percent that you believe you
actually are supposed to learn—or at least will be tested on.
If I try to avoid including in the current exam questions that were in
the webbed past exams—which is mostly what I do—a student who studies by
memorizing answers will not only waste his time in a long run sense but
in a short run sense as well, since not only will he not have learned
the subject and be unlikely to remember much of it a year or two later,
he will not even get the good grade his effort was intended to produce.
My problem as a teacher is how to get the benefit of making it possible
for the student to use the exams in the way I want him to without making
it too likely that he will use them in the way I do not want him to. I
do not have a really satisfactory solution. I tell my students how I
want them to use the old exams, but students, reasonably enough, may
suspect that my objectives are not identical to theirs, hence that
advice it is in my interest to give them may not be advice it is in
their interest to follow. I also warn the students that I try to avoid
putting questions from the webbed exams on the current one, which may be
more effective, providing they are paying attention, believe me, and
remember.
One element of the problem is the question of whether to web answers as
well as questions. One of the problems in economics, in my experience,
is that because it
deals with features of the world that students are familiar with and
uses ordinary language, often with specialized meanings, a student may
go through a course thinking he understands everything but the fine
points and end up having learned almost nothing. Having done so he might
answer all the questions on an old exam to his satisfaction but not to
mine. Providing answers makes it easier for a student to tell whether he
actually understands the subject—by how well his answer fits mine.
The disadvantage is that students may take the opportunity to memorize the answers instead of learning the course material.
At some level, my response to all such issues is that it is my job to
make it possible for my students to learn, theirs to make it happen. If a
student chooses to ignore my advice and devote his efforts to
memorizing answers in order to get a good grade on the exam, rather than
learning ideas in order to understand what the course teaches, that is
his responsibility, not mine. Along similar lines, I make no attempt to
enforce compulsory attendance. But I would still prefer, so far as I can
manage, to teach the course in a way that will make it more likely that
students end up understanding the ideas it covers.
Having discussed at some length one issue associated with giving
exams—it is, of course, that time of year—I will take the opportunity to
mention two others, starting with a policy I adopted years ago designed
to make taking exams a little pleasanter for students, grading them a
little pleasanter for me, and the resulting grades a slightly better
measure of what each student knows.
Imagine that you are a student taking an exam, and after answering all
of the questions you know the answers to you still have some time left.
It is tempting to spend the rest of the time answering the questions you
do not know the answers to, in the hope that something you write will
fool the professor grading the exam into thinking you know the answer,
at least in part, expressed it unclearly, and deserve at least partial
credit. Doing this wastes your time writing, my time reading, and adds
some additional noise to the signal that exams generate, since there is a
risk that I will either be fooled into giving you credit you do not
deserve, or interpret some other student's poorly written answer as
entirely bogus when it is not.
My solution to this problem was inspired by Socrates' explanation of why
he was, as the oracle told him, the wisest man in Athens. He was
initially dubious, since he didn't know anything. But, after extended
conversation with his fellow citizens, he concluded that they didn't
know anything either—but thought they did.
On my exams, knowing that you do not know something is worth twenty
percent. That is what you get on a question for not doing it. So if you
suspect that the best bogus answer you can come up with will be worth
less than twenty percent, you are better off leaving the question blank
or writing "I do not know," going home early, and saving me the hassle
of trying to figure out which answers are or are not entirely bogus.
My other policy, adopted several years ago, is to give short exams,
exams which I expect most students to finish before their time runs out.
My original reason for doing so was my dissatisfaction with the common
practice of giving students who can persuade the relevant university
officials that they have some invisible handicap, some sort of learning
disability, extra time on exams. While some of those students may suffer
from a real problem, I suspect that in many cases all that is special
about their situation is having parents willing to pay a professional to
produce the needed diagnosis.
I did not like being a party to what I regarded as legalized cheating. I
had no way of preventing it, but I did have a way of making it
ineffective. If everyone can finish the exam before time runs out,
having an extra hour is no longer an advantage.
That was my original reason for trying (not always successfully) to
write short exams. After I had been doing it for a while, I concluded
that it was a good idea on its own merits. Being able to do things fast
is sometimes useful, but in most contexts getting the right answer is
more important than getting it quickly. An exam that most students find
it hard to complete rewards speed by more than I think it should be
rewarded.
It occurs to me that there is one more policy of mine with regard to
exams at least worth mentioning. I only write the exam after the last
class. That way I do not have to worry, when students are asking
questions in the final review class, that I might be giving away the
answer to an exam question, unduly advantaging those paying attention at
that moment and reducing the ability of the exam to function as a
random sample of the student's knowledge.
And, for a last comment ... . I like to say that being a professor is
better than working for a living, except when grading exams. One reason
is that grading exams is a pain. Another is that it is when you find out
that you have not done nearly as good a job of teaching as you thought
you had.