Interpreting Turnitin

Turnitin Originality Reports need careful interpretation.

Turnitin reports should only be used as a guide. Before accusations of plagiarism are made lecturers must look at the assignment itself and the sources revealed by Turnitin.

It needs to be emphasised to your students that you can detect plagiarism without the aid of Turnitin’s originality checking service.

If assignments do not contain any matches this could indicate that a student has not done enough reading and referencing of other sources!

False positives

Turnitin can pick up small fragments , improperly formatted quotes, material from the bibliography. A more accurate picture might be gained form the following settings;

False Negatives

A low percentage on the report does not guarantee that you will not detect plagiarism.  Many resources are not in the Turnitin database and by using your own knowledge you would still be able to detect a suspected case of plagiarism.

What percentages are safe?

There are no clear cut rules as all work will probably contain some words from other


As a guide a returned percentage of below 15% would probably indicate that plagiarism has not occurred. (However, if the matching text is one continuous block this could still be considered plagiarism. )

A high percentage would probably be anything over 25% (Yellow, orange or red).

When checking a high ‘similarity’ value the following should be considered:

Finally: see Turnitin is an educational rather than a punitive tool.

Willful, blatant and egregious plagiarism, particularly from senior students should not be tolerated and the penalties, as laid out should be firmly applied. However, preferably we train students early to do the right thing. Here Turnitin is a useful tool because it points to where a student might be in breach of the rules. If teachers make an effort to understand Turnitin they can guide students on how to read a Turnitin reports and hence make the student the one who checks.