A cheating scandal has besmirched the U. S. Naval Academy and Virginia
Military Academy and other institutions.  As a teacher of more than 30
years, I
primarily blame this on the teachers. (Agree? Or disagree?)
For I early learned how to formulate cheat-proof tests.
In 1955, I began teaching mathematics and physics at Inter American
University of Puerto Rico, San Germ$(D??(Bn, PR.  I soon discovered that
many students depended upon little rolled-up cribs.  I announced that,
out of concern for their eyesight, I'd, henceforth, give open-book
exams with a different version for each student.  (No!  "Open-book" is
not permissive!  I'd want any person
working for me to look up critical formulas and constants.  Besides, by
not depending upon memorization, I could give them more difficult
problems than otherwise.)
I not only gave different exams to each student, but, during a trial
period, I gave different homework assignments.
Some colleagues complained that homework was optional in my class (for
reasons soon disclosed). I was assigned an assistant to help grade
papers, so I embarked upon a five-week experiment.
Each student in an "Elementary Algebra" class received five different
homework problems each class session. After four weeks, my two best
students begged for mercy.
"Sir, we've been doing the homework for most of the students.  And it's
killing us!  Our girl friends are mad because we never  have time for
them.  And our parents are mad because we never come home weekends.
Please, Sir, can you stop this?"
"I thought so.  Some of these students don't even know how to copy
correctly.  I've proven my point. So I'm stopping required homework.
And I'm not punishing you any more. I think you've had your
punishment."
(In October, 1997, a controversy developed in Fairfax County, where we
lived, when a GRADING SYSTEM was introduced which was based purely on
tests, ignoring HOMEWORK partially or totally. Parents -- many of whom
had, no doubt, done some of the homework -- objected this is "unfair".
My example above suggests that CHEATING ON HOMEWORK MAY BE GREATER THAN
ON TESTS! Even if to a LESSER DEGREE, it could contribute AS MUCH OR
MORE because of the LARGE HOMEWORK TO TESTS
RATIO.)
I accomplished this with only typewriter and mimeograph machine.  It
would be much easier with today's technology.  It's easy to insert a
formula in a computer program which generates hundreds of sets of
different numbers, placing them in blanks on an exam template.  For
non-numerical variation, a computer program could select different
synonyms or different sentence forms to make
each version unique.
In 1970, at the time of the "Apollo 13" voyage (when astronauts escaped
annililation), I gave a statistics final to 121 students at the U. of
Maine (at Orono), each with totally different numbers.
I value your opinion about my opinion.