This guide helps students understand the percentage (similarity score) displayed with a Similarity Report and offers advice on how to keep your score within target ranges, as well as what different scenarios certain scores may represent.
In this guide:
- The Similarity Report
- The Similarity Score
- What do the similarity score colors indicate?
- How do I keep my score under a certain percentage?
- How does Turnitin identify student collusion?
- Similarity score scenarios
The Similarity Report
Turnitin does not check for plagiarism. What we actually do is compare your submission against our database. Our database includes current and archived content from the internet, thousands of periodicals, journals, and publications, as well as a repository of works other students have submitted to Turnitin. We then highlight wherever your writing is similar to text from any of our sources.
The Similarity Report provides a summary of details, including the sources matched to your submission, to use as a tool to determine if the matches are acceptable. When a Similarity Report is available for viewing, a similarity score percentage is displayed.
The Similarity Score
The similarity score is the percentage of matched text your submission contains, or overall similarity. We calculate this by dividing the total words in a submission by the amount of words matched to outside sources.
It is likely your submission will match against some of our database. If you've used quotes and references correctly, that will still be highlighted as a match.
If a similarity score does not appear under the Similarity column, there could be two reasons:
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Your instructor turned off student access to the Similarity Report
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The Similarity Report is still being generated and will be updated once it has finished processing
Overwritten or resubmitted papers may not generate a new Similarity Report for a full 24 hours. This delay is automatic and allows resubmissions to correctly generate without matching to the previous draft.
What do the similarity score colors indicate?
Feedback Studio • Feedback Studio w/ Originality • Originality Check
For classic assignments, the color of the report icon corresponds with the similarity score of the paper.
The percentage range is 0% to 100%. The possible similarity ranges are:
- Blue: No matching text
- Green: One word to 24% matching text
- Yellow: 25-49% matching text
- Orange: 50-74% matching text
- Red: 75-100% matching text
Similarity • SimCheck
The color of the similarity score in My Files is based on the amount of matching text in a document.
The percentage range is 0% to 100% with the possible similarity groupings being:
- Green: 0% matching text
- Blue: 1-24% matching text
- Yellow: 25-49% matching text
- Orange: 50-74% matching text
- Red: 75-100% matching text
How do I keep my score under a certain percentage?
There is no fixed number to receive as a score in your Similarity Report. Every school, instructor, or assignment could have a different amount of matching text that is considered acceptable. Before submitting:
- Consult your class syllabus, check assignment instructions, or ask your instructor for similarity score expectations.
- Review your institution's policies on what counts as an acceptable similarity score.
- Properly cite each source that you reference.
A high similarity score could mean that very little of your paper is your own writing. To address a high percentage, consider the following:
- Balance the information that you use from texts with your own writing.
- Determine when it would be most appropriate to paraphrase, summarize, or explain an idea in your own words.
Zero similarity may indicate that you aren’t including any source-based evidence, a requirement for many assignments. Some similarity is expected. To address a low percentage, consider the following:
- Balance your own writing with the information that you use from sources.
- Determine when it would be most appropriate to quote directly from a source or paraphrase information to add research-based support for your claim.
How does Turnitin identify student collusion?
Collusion is typically identified when a student's work matches with another student's submission on the same assignment or to previously submitted papers. Consider the following scenario:
Eric acquired a copy of his classmate Jane's paper. Eric submits Jane's paper as his own and receives a similarity score of 25%. Jane, who originally wrote the paper, submits her work a few days later and receives a 100% similarity score.
Turnitin can identify that collusion has taken place in this scenario by running a final similarity check against all submitted assignments after the due date. This ensures that every student is subject to the same level of scrutiny, regardless of when they submitted their assignments.
Similarity score scenarios
A high similarity score does not always suggest that a piece of writing has been plagiarized, just as a low similarity score does not always indicate that no plagiarism has occurred. Consider the following scenarios:
- Submitting a document of considerable size could result in a 0% similarity score with a report that still contains matches. This is because the similarity score has been rounded to 0%, rather than being exactly 0%.
- You may have submitted multiple drafts of the same paper to your institution's private repository, meaning your final draft has resulted in a score of 100%. To avoid this issue, we advise that you only submit your final draft to the private repository.
- An individual within your institution has managed to acquire a copy of your document. They submit this document to the institution's private repository and receive a similarity score of 25%. You submit your original document a week later to the private repository but receive a 100% similarity score.