From Alex Halavais:
At some point, the spy v. spy effort to contain cheating seems to occupy far more time than it is worth, and you fear you are neglecting the students who really are there to learn. In many ways, the propensity for students to cheat on the exams is a symptom of an educational system that has failed. If we cannot teach our students the value of learning, rather than the value of the GPA, we really are not very good at our job.
Read the comments thread too…
I taught high school math courses for ten years and every test I gave was open book, open notes – closed neighbors. It is much harder to create a test that challenges the student to think, than to simply recall information. But the result is that students are forced to learn, not simply memorize. If we required all teachers to give open book tests, it would force them to better prepare the students. After all, when you leave school, the rest of your life is open book tests.