In CAT applications, students do not take the same test. Despite item numbers and properties of items are different for the students; the precise of measures improves in positioning students on an ability or success continuum in CAT applications. In CAT applications, questions answered by a student depend on the student's ability or learning level. In item response theory, there are some models to estimate a student’s ability level, such as three-parameter logistic model. Cheating in exams or other academic assignments can be defined as use resources not allowed to use or having someone else to take exams or assignments. Some precautions must be taken about cheating such as a live proctoring, using web cams, and using a plagiarism detection program.