Turnitin - Similarity Reports
One of the key benefits of using Turnitin lies in its ability to determine whether work submitted by a student is original, or whether it contains matches to Turnitin’s repository of a wide range of web based materials and other student submissions.
Once a Turnitin assignment has been submitted by a student, a Similarity Report will be generated according to the settings chosen when the assignment was set up. When a student submits an eligible file type (as below) to a Turnitin assignment, it is then matched against web pages, journal articles and papers previously submitted to Turnitin, to produce a Similarity score.
(Note that Similarity Reports are not always generated instantaneously and there may be an hour or more delay after submission before they are available. Moreover, multiple submissions by a single student for the one assignment will involve a delay of up to 24 hours before the Similarity Report is generated.)
When the report is available, a number and coloured square will appear next to the student’s submission. This number is the Similarity score and represents the percentage of the student’s submission that matches text in Turnitin’s repository. Clicking the percentage or coloured square opens Feedback Studio to view and grade the paper with the Similarity layer active on the screen. The Similarity Layer contains information about the matches.
File types that Turnitin can check for Similarity
Only the following file formats are able to be checked by Turnitin in order to generate a Similarity Report:
- Microsoft Word
- Corel WordPerfect
- Adobe PostScript
- Google Docs
- Plain text.
If staff select the option to allow students to submit “any file type”, students are able to submit documents that will not be checked for Similarity, for example images, audio, movies and zip files. Files not eligible for Similarity checking will appear with a double-dash in the Similarity column of the Assignment Inbox.
What Similarity percentage is safe, and what percentage indicates plagiarism?
Having a high percentage does not necessarily mean that a student has plagiarised and conversely, having a low percentage does not necessarily mean that a student has not plagiarised. In all cases a content expert (lecturer/coordinator) will need to make a judgement call to determine if plagiarism has taken place as there is no magic percentage score that indicates this.
For more information on the common myths surrounding Turnitin Similarity Reports, see the various guides on this page.
Turn the Similarity Reports setting 'On'
Similarity Reports are an optional setting when creating an assignment. Select Yes if you want Turnitin to generate Similarity Reports for a particular assignment. This setting should be turned on before students submit to ensure timely reports. Markers can turn the setting on after student submissions have been made, but there may be a delay before the reports become available.
Access Turnitin Similarity Reports
- From the Control Panel select Subject Tools, Turnitin Assignments.
- Click the title of the Turnitin assignment you wish to access.
- To review a Similarity Report for a student submission, click the coloured square or percentage number displayed in the Similarity column. A new window containing the report will appear.
- The student paper shows highlighted text, indicating text that matches something in Turnitin’s repository of web content and other student submissions.
- The Similarity layer toolbar appears on the right hand size of the page, showing options for Match Overview, All sources, Filters and Settings, and Excluded Sources. Note that at any time you can turn the Similarity layer on or off by clicking the top part of the Similarity layer icon. Turning the Similarity layer off will stop highlighting any similar text in the document.
The Match Overview icon represents the percentage of the student’s work that matches text in Turnitin’s repository. Clicking on the number shows the various matches in the student assignment, listed from highest to lowest percentage, with each match coded in a different colour. Each of these matches is considered the best, or top match for that particular excerpt of text in the student’s assignment. It is important to remember that there will usually be a number of possible sources for each match, due to frequent duplication of text on the web, but Turnitin shows the most likely option.
Click one of the matches in the Match Overview panel to see where it is located on the student’s paper. The student’s words and phrases will be highlighted in the context of the source it matches. Click the URL to be taken to the relevant website that the match is from.
You can also click on the flag icon on any of the highlighted text on the student’s assignment to bring up this same information.
In the Match Overview panel, use the arrows on the grey bar “Match 1 of x” to find other matches in the student’s work for that particular source.
Click the right-hand arrow on one of the matches to see the Match Breakdown which shows all the alternate possible sources that could also be a match to that section of text.
The All sources icon allows you to view a full list of all matches found instead of just the best or top matches for each match.
Sometimes it may be necessary to exclude some sources from the Similarity Report, for example, a student’s work might be matching itself, or you may want to clear a particular match. When looking at the Match Breakdown, or the All Sources view, you can exclude certain sources by selecting Exclude Sources at the bottom of the page, then ticking the box next to sources you wish to exclude, then clicking Exclude again at the bottom of the page.
Filters and Settings
The Filters and Settings icon allows you to limit or modify the way Turnitin checks for Similarity matches. For example, you might wish to exclude text that is inside quotation marks, or perhaps instruct Turnitin to ignore matches that are less than a certain number of words, or even to ignore the References section of a student’s assignment. Best practice advice however, is not to use any filters, but rather to allow Turnitin to check for all matches, and then allow the marker to make the call as to whether a match is a problem when reviewing the assignment as a whole. If you have made changes to the Filter sand Settings, you will need to click the New Report button to generate a new Similarity Report based on these new match settings. Note that the new report may take some time to be generated.
The Excluded sources icon allows you to review anything that you have excluded from matching and restore the matches if necessary.
Matches to student submissions
As well as matching web and electronic sources, Turnitin can also match submissions against previous student submissions. Where this is the case, the marker will be able to request access to the paper that is a match. To request access, click the match, then click ‘Submitted to the University of …”. A new window will open allowing you to enter your email address so that the matching paper is sent to you.
It is up to the administrators of the matching paper to decide whether to share the paper with you. Note that Turnitin is used not just at the University of Melbourne, so you may see matches from other institutions. A student’s work may also match itself if the student has accidentally submitted the paper elsewhere, or has copied their own previous work.
Removing documents from the Turnitin Repository
Sometimes it may be necessary to remove a document from the Turnitin repository. For example, a student may have submitted their own draft work accidentally which is inflating the Similarity score on all subsequent submissions. If you need to have a paper removed from the repository, submit a support request for assistance.
Download/Print a student’s Similarity Report
The grey section of the toolbar allows you to download the student’s paper showing all marking, feedback, and if the Similarity Layer is active, the Similarity Report.
- Ensure the similarity layer is active by clicking similarity layer icon
- Click the Download icon
- Choose Current View
- Save the file to your local computer and/or Print as needed.
Similarity Report statistics for a class
Turnitin allows you to view some statistics pertaining to the Similarity results for a particular subject.
- Open the Control Panel of the subject containing the Turnitin Assignment.
- From the Subject Tools module select Turnitin Assignments.
- Click the Turnitin assignment to be checked.
- The Assignment Inbox displays by default.
- Click the Class Stats tab.
- The class statistics are displayed for all assignments and include: number of submissions, number of people within each % range in the Similarity Reports, number of Peer reviews and QuickMarks, plus a breakdown of which QuickMarks were used.
Further information on interpreting Similarity Reports
Student access to Similarity Reports
At the discretion of teaching staff, students may be given permission to view the Similarity Reports for their own submissions on Turnitin (this is set by clicking + Optional settings when creating the Turnitin assignment). Similarity Report preferences are selected on an assignment-by-assignment basis and may be updated by teaching staff via Edit Assignment. Options include allowing students to view immediately first report is final (one submission only), immediately (can overwrite report until due date), (i.e. multiple submissions allowed, 24 hour delay on displaying Similarity on subsequent submissions) or on due date.
Access Turnitin Similarity Reports by groups
This function requires groups to be already created within your subject. For information on creating groups: http://www.lms.unimelb.edu.au/teaching/communication/groups/
- From the Control Panel select Subject Tools, Turnitin Assignments by Groups.
- Click the title of the Turnitin assignment you wish to access.
- Select a group from the pull-down menu and click Go.
- To review an individual Similarity Report for a student, click the title or the Similarity score.
- The student submission will open up in a separate browser window for viewing/marking.
- The navigation options in the top right corner do not allow you to navigate through one particular group only, but rather will browse through all student assignments in alphabetical order.
- If planning to use Turnitin by groups for assignments where students are not required to provide a submission, the Grading Template needs to be created from the Assignment Inbox, before assessing the groups.
This guide was last updated 31 Aug 2018.
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