The Similarity Report is the result of a comparison between the text of the submission against a large range of sources in the Turnitin database. Examples of resources checked are:
- Internet sites and archived internet documents and data
- A repository of papers previously submitted to Turnitin
- A subscription repository of periodicals, journals, and publications
If matches are found, Turnitin will highlight the matching text and provide links to the identified sources in the similarity report. Turnitin also gives a ‘similarity score’, which is the total percentage of text in an assignment that has been matched to other sources. 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
Tip: there is no ‘ideal’ percentage threshold in a Turnitin Similarity Report. A ‘similarity score’ must be interpreted on a case by case basis, and it is important to remember that a high ‘similarity score’ may not be an indication that there is any inappropriate content in an assignment.
For assignments, the Similarity Report can be accessed from the Assignment Inbox. Select the similarity score from the % column to open the document viewer. The score sits alongside its corresponding color.
For forum, the Similarity Report can be accessed underneath the student’s post:
View the Similarity Matches
Similarity report displays the original student work in the left-hand pane and the Match Overview in the right-hand pane of the window.
- The Match Overview (show highest matches together) is a list of all areas of the paper which have similarity to text in the repositories the paper is being compared with. Matches are numbered, color-coded, and listed from highest to lowest percentage of matching text to the submission. Only the top or best matches are shown, all underlying matches are visible in the "Match Breakdown" and "All Sources" modes.
- To view all sources, click the red All sources icon from the similarity toolbar. If the similarity layer was inactive, it will now be activated, highlighting all on-paper matches.
- To access each match in more detail, click the arrow to the right of each similarity percentage.
- The Match Breakdown will display all sources identified for each match. To view the sources on-paper, simply click on any source in the Match Breakdown.
- A source box will appear on the paper, revealing where in the source the text has been identified. If you would like to read the full source, click the book icon in the top right-hand corner of the box. You can also access this source box by clicking the red match flag to the left of the highlighted text.
Interpret the Similarity Report
Turnitin reports will be color-coded and provide some indication: blue or green indicates that it is unlikely plagiarism has occurred, or yellow, orange and red indicates that it is highly likely something is amiss. However, faculty need to understand that a report generated from Turnitin must be examined. All matches need to be reviewed in order to determine the level of possible plagiarism.
Given that students are expected to include evidence and examples from a variety of sources in assignments, it is to be expected that academic work will always contain matches resulting in a ‘similarity score’.
Matches could occur for the following reasons:
The presence of phrases.
- A direct quote might have been made in an assignment. This provides students and lecturers with an opportunity to check that direct quotes have been correctly referenced.
- A student might have copied someone else’s work, be it another student’s paper, recycled their own work, or taken material directly from some other source and made it appear to be their own; this is plagiarism.
The presence of common language
- An indirect quote might have been included in an assignment which is very similar to the original. If a match in Turnitin occurs due to paraphrasing, it may generally indicate that the paraphrasing is too similar to the original and needs to be rephrased.
- Some specialized areas often use common language. For example, it can only be said just so many ways how chemical compounds work together or how Lord Byron was born and where.
The presence of the bibliography
You can recalculate the report and exclude low‐level matches, the bibliography or both. Doing so will likely decrease the similarity score.
Refine the Similarity Report
- Exclude small sources (measured by word number of percentage)
You can exclude sources in the source list that are below the threshold set by you. For example, if the threshold is set at 3%, any 1% or 2% match would be removed from the current report mode's source list (Match Overview or All Sources).
- Exclude quotes and bibliography
Quotes and bibliography items are widely reused and generally fail to demonstrate original writing. You may wish to exclude quotes, bibliographies, and items of a similar nature from influencing your students' similarity scores.
- Exclude full sources
The source exclusion feature is generally used when a paper has been submitted more than once to Turnitin (possibly as draft submissions). Sources may also be excluded when an instructor agrees that students use a certain source for their writing.
- Generate a new Similarity Report
If you believe an item may have been added to the Turnitin database since a Similarity Report was last generated (this could be a website, journal article, or even another student’s paper), you can generate a new report to receive an up-to-date score.