(2) Some low-percentage matches can still be substantial. Instructors must carefully review the actual matches flagged in a similarity report. Disciplines have drastically different standards of how much similarity is acceptable.Įven a long passage with substantial similarity may be acceptable in some fields or in some genres, depending on how clearly the student credits the original source.įor these reasons, no conclusions can be drawn from the similarity score alone.Here, for instance, are two passages Turnitin highlighted in sample papers but that would usually not be considered plagiarism: “the fear conditioning deficit model and the response modulation model” and “The inner boundary habitable zone is 0.335 AU, while the outer boundary habitable zone is 0.705 AU.” Such phrases are especially common in science and social science writing.

Turnitin sometimes flags phrases that a discipline has established as technical names for key concepts, or language that everyone in the discipline uses to define a common idea.

Turnitin sometimes flags text that the student has placed in quotation marks or in block quotations, even though the settings try to avoid these matches.

Titles are often long enough to produce a high similarity score.

Turnitin sometimes flags titles that the student has listed in the text, footnotes, or bibliography.

There are a number of reasons for what we might call false positives-passages highlighted by Turnitin that turn out to be properly cited: (1) A high similarity score, on its own, offers no evidence of a failure that a student has failed to use sources properly. Both papers with (1) high and (2) low similarity scores still need further review.

The similarity score on a Turnitin report is nearly meaningless without interpretation.

Turnitin originality report