I gave my students a take home exam over spring break. (This is normal where I teach) One of the questions was particulary difficult. It came down to a factor of three in the solution. That factor inexplicably appeared with no justification on many of their exams. I intend to have the students I suspect of cheating come to my office to solve the problem on the board. What would you do?
Edit: I gave them the Tuesday before spring break until the Thursday after. I didn’t want it to be right before or right after.
When I say normal I mean giving take home exams.
I wouldn’t do anything. Your job is to teach, not to discipline. Your students can choose to do or not do whatever work you set them; it’s their education and their choice. Ultimately cheating only affects them and their learning.
Also, seconding the fact that if you give people a graded take home exam that implies open book (including the internet and each other)