Plagiarism Detection using Turnitin

Turnitin is a plagiarism detection service. The software takes an assignment which you upload to the Turnitin servers and compares it with other assignments in its database. This database is composed of other student assignments which have been submitted for checking, pages retrieved from the World Wide Web, and published works of various kinds. If the software finds similarities between the submitted assignment and anything else in the database, these are highlighted in a report.

You can see a demonstration of the service, which includes a sample report, on the Turnitin website.

There is a set of guides to using Turnitin in the MMU Staff Resource Area in Moodle (MMU staff only). Go to the Moodle section, click on Technology Enhanced Learning Guides and Training, then scroll down to the Online Assessment section. This includes a detailed, step-by-step guide to setting up an assignment , including a form of words to use with the assignment which provides a link to the Turnitin usage policy.

Your faculty Technology Enhanced Learning Advisor (TELA) will also be able to help with the technical aspects of using Turnitin and may run staff development sessions. TELA contact details

Use with care

  • Although Turnitin provides a useful set of tools as part of an originality report to help in determining if a piece of work is plagiarised, you need to interpret the results with care.  As a plagiarism detection tool it is only as good as the interpretation we put upon the similarity report: the measure provided on the report is of percentage similarity, not percentage plagiarism.
  • We recommend that you always set up the assignment in Moodle to exclude quotations and references, but if a student uses single rather than double quotes, for instance, this may not help. You can also set it up to exclude short sequences (eg a particular number of words)., which reduces the chance of common phrases coming up constantly – this is particularly likely if your discipline area has a lot of specialist terminology. It is sensible to look at the originality report and and check whether the colour coded sections may actually have been correctly cited. 
  • The biggest clue to plagiarism is long blocks of the same colour in the originality report.    Assignments could have a high similarity ‘index’ but actually be very extensively referenced and have used quite a few direct quotes that are properly cited (of course it is a matter of judgement what impact this has on the marks for a particular assignment).  You could have a low similarity where a whole section had simply been cut and pasted without any citation, which would be plagiarism. 
  • One approach is to scan the list of submissions and have a quick look at the reports for any which look out of kilter with the others – the actual percentage of similarity which bothers you may vary depending on the type of assignment. Very low matches may attract attention as much as higher ones. There really is no magic number. Then look through the reports to see what kinds of things are being matched – often the matches may be several repetitions of fragments of fairly common phrases – this is particularly true if the assignment covers technical language, for instance. Or you may find that some students do things like include the assignment brief in the appendix – which instantly results in a large percentage match if there is more than one student does this. These may not be common occurrences, but are mentioned to illustrate that there is no substitute for tutor scrutiny and interpretation of a report.

Steve Bentley at the University of Huddersfield has developed a card game to help teach students how Turnitin is used. He has made it available as an open educational resource at http://eprints.hud.ac.uk/30172/.