A cheat sheet (also cheatsheet) or crib sheet is a concise set of notes used for quick reference. Cheat sheets were historically used by students without an instructor or teacher's knowledge to cheat on a test or exam. In the context of higher education or vocational training, where rote memorization is not as important, students may be permitted (or even encouraged) to develop and consult their cheat sheets during exams. The act of preparing such reference notes can be an educational exercise in itself, in which case students may be restricted to using only those reference notes they have developed themselves. Some universities publish guidelines for the creation of cheat sheets.