Keep copies of student work. As the school year progresses, compare his current and previous work to examine discrepancies or clear cases of outside help.
Use online search engines to check questionable sentences, lines or quotations that seem out of place in student work. Students who plagiarize commonly use information from the Internet that is easy to find.
Upload student work to online plagiarism detectors that run the material against an expansive database of student essays, published work and other material to determine the likelihood of plagiarism. These programs, such as iThenticate and Duplichecker, can detect when students have merely added sentences or changed words and give a good idea of the likelihood of plagiarism. See the Resources section for more information.
Inform your students that all materials will be checked for plagiarism. Require digital copies of all work if possible to make it easier to use online plagiarism detectors. Make your students read your school's honor or academic honesty policy so they are aware of the consequences of plagiarism.