Has anybody observed cheating?
RiderOfGiraffes: I can't be too specific about the circumstances ...A colleague of mine was teaching a class, and after a few weeks set a test.  He also took a note of who sat where, and noted that three friends, A, B and C, were sitting together in the back.  When he graded the test he found that on question 3, A and B had identical incorrect answers, whereas on question 7, B and C had identical incorrect answers.  He joked that this showed that A and C were conspiring to make it appear that B was cheating, but the evidence was clear - cheating had occured.  He decided it was an interesting lesson for him, and it was OK since that test only counted for 5% of the final grade.For the next test he created two, nearly identical tests, differing only in the actual numbers.  All the calculations were identical, just the numbers were different.  He gave these out alternately.As office hours approached on the day after the graded tests were returned, there was a very long queue.  He invited the first student in, who immediately started complaining that on question 6, he and his friend had identical answers, but his friend got full marks and he got zero. "But the questions are different," said my colleague.  "But the answers are the same - why don't we get the same grade?" complained the student.  After running around that little loop for a while the light dawned, the student became very thoughtful, and left.  "Next!" said my colleague.  No one came in, and when he checked, the queue was gone.The students complained to the Dean, and my colleague was told in no uncertain terms that it was unacceptable to give different tests.  In particular, it was unfair not to have warned them, or made it obvious. The students had no way of knowing that they were equivalent, it was impossible to prove that they were equivalent, so he was instructed to give identical tests to everyone.On the next test he handed out alternate blue and yellow test sheets.  There was muttering, but no outright complaints.  Within an hour, however, he was summoned to the Dean's office.  "You were told to give identical tests!" shouted the Dean.  "I did", said my colleague.  "They were on different colored paper, but they were identical tests."The reaction from the Dean was, says my colleague, remarkably similar to that of the student discovering that the tests were different.Fortunately that was the last "in class" test.  The final loomed, and one by one the students dropped the course.  The final test was only taken by 12 of the initial 40 students, and all passed.  Interestingly, of those that dropped out, several were later disciplined for cheating in other classes.So the evidence suggests that cheating occurs.But we knew that.