Some students cheat. Here’s how they do it (from least to most frequent) and what you can do about it.
Having someone else take the exam
Desperate students use desperate measures. The most extreme form of cheating is to have someone else take an exam and pretend to be you. This obviously only works in large courses where the professor doesn’t know all individuals. The solution is simple: require students to bring a picture ID to the exam and compare the photo to the face and the name on the ID to the name on the exam paper.
Changing answers and claiming more points
Some of my students have taken an exam, received the graded paper, modified their answers according to the answer key and resubmitted their paper for regrading. To detect this type of cheating, I scan all exams before handing them back to students and then compare the two versions. And since I don’t like failing students, I tell them what I do beforehand to deter them from even trying.
Using cell phones during an exam
I require my students to turn off their cell phones before the exam and to leave them with me when they leave the room for a restroom break. However, an enterprising student could bring in a second, hidden cell phone. To minimize the advantage of hidden cell phone usage, I allow my students to bring a sheet of notes (see below) and turn off the online homework system during the exam (as my exams tend to be heavily based on the homework problems).
I do not consider collaborating on homework assignments cheating, and in fact encourage students to do so. However, to make sure that students do not blindly copy each other’s answers, it is best to give every student different questions. The only practical way of doing this is by using an online homework system that generates different input numbers for each student.
Using cheat sheets (aka crib notes)
Using a set of hidden notes (on paper or programmed into a calculator) during an exam is a classic cheating method and nearly impossible to stop, since students can always use a restroom break to look at their notes. Therefore, I allow my students to bring one letter-sized sheet of handwritten notes to the exam. One advantage is that students who create such a sheet actually learn a lot in the process.
Copying others’ answers
To make it more difficult for people to copy each other’s answers (by peeking or whispering), you can require students to spread out and leave a vacant seat between each other. However, my classrooms are typically not large enough to make this a feasible solution. I therefore use different versions of the exam. An online homework system like Accepi makes it easy to change input numbers with one click and create different versions of an exam.
Lastly, you should put some strong language into your syllabus, e.g., “Anyone found cheating in this course will fail the course and will be reported to the administration for additional disciplinary actions.” Spelling out the consequences of cheating at the beginning of the term will deter many students from cheating.