Turnitin

Help Center: Similarity Index by Source

Instructors can view a breakdown of which repositories a paper was found to have matches to within the detailed Similarity Index. Users can view the detailed Similarity Index in the Originality Report (at the top of the report). A percentage is listed next to the name of each target repository. That percentage represents the total percentage of the paper that was found to match sources within that repository. Be aware that there may be overlaps in the matches between repositories causing the sum of each repository percentage to be greater than the Overall Similarity Index (which is the total percentage of the paper found to have matches to any repository minus exclusions) or even to be greater than 100%.

How to view the detailed Similarity Index in an Originality Report

1. Click on the class name

2. Click on the "View" link to the right of the assignment name

3. Click on the Originality Report icon

4. The similarity index located on the top right of the screen will contain the overall percentage and the percentage of matching content from each of the three Turnitin repositories: Internet Sources, Publications, and Student Papers (refers to papers stored in the standard paper repository and the institution's paper repository)

Note: Sometimes the overall similarity index may be a smaller percentage than the repository percentages combined. This would be due to overlapping text within the repositories. The overall similarity index combines all the best matches from the overlapping sources.