A Similarity Report Score is not a definitive indicator of plagiarism. The score reflects the percentage of matching content between the student’s submission and various sources in Turnitin’s extensive database. However, this score is influenced by how the instructor sets up the Turnitin assignment. It’s essential to examine the details when interpreting these scores, as they should be assessed on a case-by-case basis, considering the context of the assignment.
False Positives
A high similarity score does not always indicate plagiarism. Some common reasons for high scores include:
- Indexed Drafts: The student may have submitted an earlier draft of their paper, and that draft was indexed in Turnitin’s repository, causing matches to the current version.
- Commonly Used Phrases: Standard academic phrases or widely cited references can lead to matches.
- Common Assignments: In some cases, thousands of students may write similar responses to the same assignment prompt. For example, introductory philosophy papers on Descartes’ Meditations often contain similar sentences or phrases because of shared references and limited variation in student perspectives.
- Reuse of Student Work: Students may have reused content from their previous assignments. Ensure assignment instructions clarify whether this is permissible.
- Peer Matches: Another student may have copied the original student’s work, and the Similarity Report identifies these matches. The report does not distinguish which text is the original and which is the copy, so further investigation is necessary.
- Draft Coach Similarity Check Limit Exceeded: Draft Coach allows only three originality checks per unique document. After the third check, the document’s content is automatically submitted to the institutional repository, which may result in matches against the student’s own work in future submissions.
False Negatives
A low similarity score doesn’t guarantee originality. Plagiarism may still exist under circumstances such as:
- Sources Not in Turnitin: Content from sources outside Turnitin’s database won’t be flagged.
- Effective Paraphrasing Without Citation: The student may have paraphrased the original content sufficiently to avoid detection by Turnitin but failed to cite the source, which still constitutes plagiarism.
- Third-Party Assistance: The student might have asked someone else to write the paper, such as another student or an external source.
By understanding the nuances of these scores and investigating any unusual results, instructors can use Similarity Reports as a helpful tool in maintaining academic integrity while also providing valuable teaching moments for students.
Submission Retention and Indexing in Turnitin
When students submit assignments through Turnitin, their work is retained in Turnitin’s repository unless otherwise specified by the instructor. Submissions in the repository serve as a reference for future originality checks, comparing new work against previously submitted assignments from students worldwide.
Consequences of Submission Retention
- High Similarity Scores: Retention of submissions can result in high similarity scores if students reuse their own work or if their content closely matches other students’ previously indexed assignments. For example, a student submitting a revised draft of a previously submitted paper may see a high score due to matches with their earlier draft.
- Self-Plagiarism: Students may inadvertently violate academic integrity policies by reusing their work without explicit instructor approval. UGA’s Academic Honesty Policy considers reusing one’s prior work without permission as prohibited conduct. Ensure assignment instructions clarify expectations regarding self-plagiarism.
Adjusting Retention Settings
Instructors have the option to customize Turnitin’s retention settings for assignments. These settings allow for greater flexibility in how submissions are stored and compared:
- Institutional Repository: Submissions are retained within UGA’s internal database, ensuring they are only compared to work submitted within the university.
- No Retention: Submissions are not stored in the repository, making this option ideal for drafts or assignments where retention is not needed.
Recommended Best Practices
- Communicate Policies: Clearly outline expectations around submission retention, self-plagiarism, and originality in assignment guidelines.
- Allow Draft Checks: Setting the assignment to “no retention” allows students to review similarity reports for drafts before final submission, helping them identify and address concerns early.
- Leverage Retention Settings Thoughtfully: For courses with multiple drafts or iterative assignments, consider using non-retention settings to prevent inflated similarity scores due to matches with previous drafts.
Additional Resources
