[wewyor]

I think it really depends on the students and whether or not you are finding these coasters (taken from other comments) in the classes or not. Cheating is probably the least likely in the harder degrees near the end of the program and most likely in the easier degrees near the beginning of the program.

In my engineering program I have had plenty of teachers walk out of the room for large amounts of time or do something like grade papers without looking around the room and haven't once seen an issue of cheating.

However in my freshman chemistry course which was required for a large amount of students from many disciplines they had 8 T.A.s and electronically moveable cameras (the class was recorded so the cameras were just being re-purposed) monitoring a class of about 200 and I do believe some cheaters were caught in my semester.