A lot of things fall under the general heading plagiarism. Not all of them need to be handled the same way.
The most obvious form of plagiarism is collusion, where a student has turned in a paper written by someone else. Certainly in cases of collusion, you will want to contact Student Judicial Services to decide how to proceed.
Other things that fall under the general heading plagiarism are instances where students haven’t cited sources properly. In these cases it may be useful to consider the question “Why not?” Citing sources is a learned activity, and students’ learning about it varies. Even students who know how to follow the rules of a particular citation style, such as MLA, probably do not know the appropriate citation methods for all of their college courses. Citation styles can be particularly tricky for students who come from other cultures, which may have different conventions about how authorities are treated in paper, and different assumptions about what audiences know and don’t know. Frequently, students try to document sources correctly but make mistakes.
There’s only one way to be sure students know what to cite and how to cite it correctly in your field: Teach them. If you give them opportunities to try, fail, and get it right before turning in a major assignment, you will have far fewer instances of sloppy citation on a final draft. The UWC can help. If your assignment indicates which style guide students should follow, our consultants can help them learn to cite sources correctly.
Occasionally professors ask us if we can recommend an online tool to check for plagiarism. In our experience, the best tool is Google. Dr. Susan Schorn, Writing Program Coordinator in Undergraduate Studies, has run a number of tests that prove that Google is better at identifying replicated text than TurnItIn and similar products (which also have a high rate of false positives). Rather than running entire batches of papers through TurnItIn, you can copy passages that you suspect may be plagiarized and run them through Google.
The following pages from the websites of the Department of Rhetoric & Writing, University of Texas Libraries, and Undergraduate Studies provide resources to help you prevent plagiarism in your classes and handle cases that arise.