When a student submits the same paper multiple times, Turnitin handles the similarity matching differently based on whether the assignments belong to the same class or different classes.
Submitting to multiple assignments in the same class
If a student submits the same paper to more than one assignment within the same class, Turnitin automatically prevents these papers from matching against each other.
Why this happens: This default "self-match exclusion" is designed to allow students to submit early drafts of their work without their final submissions matching against their own previous drafts.
Where to find them: These internal matches are automatically hidden but can be viewed in the Excluded sources section of the Similarity Report, where they can easily be re-added to the report if necessary.
Submitting to assignments in different classes
An automatic exclusion does not occur if a student submits the same paper to assignments across different classes, provided at least one of those assignments was configured to save papers to the standard Turnitin repository. If required, instructors can manually override self-matches by excluding the match.
Managing exclusions
For step-by-step instructions on how to manually hide or restore matches, please refer to our comprehensive guide on Managing exclusions and filters in the Similarity Report.