Yale Center for Teaching and Learning

Unattributed Sources & Multiple-Submission (Self-Plagiarism)

Unattributed Sources

A Turnitin similarity report highlights passages in your paper that use very similar language to passages in another source. If Turnitin has identified such passages, the first thing to check is whether you’ve given credit for these passages to the source.

How a writer gives credit to a source varies slightly by discipline, but usually involves a footnote, a mention of the author’s name in parentheses, or a mention of the author’s name directly in your own paragraph. The Poorvu Center website offers guidance about Signaling Sources in your papers.

If you’ve given credit to the source, but then decide that you’re still using too much of its language, you can try reducing the volume of quotations, or Strategies for Paraphrase to use more of your own original language.

Unattributed Sources by Other Students—If Turnitin identifies similarities with a paper submitted by another Yale student, you will need to ask your instructor about the course policy on collaboration. Collaboration on assignments is restricted as per the Yale College Regulations.


The most common similarities that Turnitin highlights are to published sources. Once you start taking multiple courses in the same academic discipline, Turnitin may also start to find similarities between the current paper and one you’ve written for a previous class. If you want to use any material from a paper you’ve written before, you must get permission from both instructors. Be sure to talk to your instructor about what’s allowed. Situations like this are covered by the Yale College policies on Multiple Submission.