How to interpret Turnitin originality reports

This page has been replaced by How to use and interpret Turnitin similarity reports and will soon be deleted. Please update any documents or guidance that link to this page so that they link to How to use and interpret Turnitin similarity reports instead. You can find all our updated Turinitin guides in our Turnitin space.

Logo for Turnitin

Turnitin is a third-party service used at LSE to identify similarities between student submissions and other sources. For guidance on reading reports, see below. For answers to common questions, see the Turnitin FAQ. For help enabling Turnitin, see: Setting up Turnitin Originality Reports for Moodle Assignments.


How to use and interpret Turnitin Reports

Turnitin Originality Reports

Why use it?

TurnItIn is a service that matches text from student assignments against its extensive databases of previously submitted student coursework, websites and academic papers. Turnitin produces an originality report and a score (%) of matched text.

It is a text matching tool, not a plagiarism detection tool. Therefore, to use Turnitin to support academic misconduct, we recommend that interpretation of Turnitin reports should be the responsibility of academic colleagues.

Turnitin provides a useful indicator to Markers of the extent of matched text within a document, but it cannot determine what those matches mean. It is no replacement for academic knowledge and judgment in determining cases of academic misconduct/plagiarism.

You can read more about current Turnitin practice across the School and our recommendations for its the use in our Guidance for Turnitin use during the Summer assessment period.


How to view a student’s originality reports?

  • Go to the Assignment where you wish to view reports and click View all submissions

  • Within the submissions table you will see a column entitled File submissions

  • The Turnitin report sits under the student’s submission. Click on the percentage score to view the report


The main window shows the student’s work. You can scroll down to see all the pages.


A side bar on the right hand side shows a number of tools related to Instructor Feedback (blue), Similarity (red) and Download/Submission (Grey).  For the purposes of this guide, we are only concerned with the similarity tools (red).




Make sure the Similarity layer button is red – if it’s black, click it to turn it red and reveal the similarity matches.



Identifying matches

Within the student’s work, you may see sections of the essay have been highlighted, each with a number and colour. Turnitin highlights phrases which match another source (an e-book, website, e-article, or other submitted student work). The number refers to the matched source identified.  

Things Turnitin may not search, or cannot match, include:

  • Print sources, particularly older sources

  • Some online materials (particularly pay-walled materials) including many journals

  • Your own handouts or other course materials

  • Anything translated from another language by the student

Turnitin can’t help as much with:

  • collusion - it can match two submitted essays but can’t indicate who is the original author of any section

  • essay mills – Turnitin can’t prove authorship (try checking the metadata of the submitted file)

  • ‘self-plagiarism’ from a previous essay by the same student – unless the other essay was submitted to Turnitin’s repository


Matched Sources

When you click on the number (percentage similarity score) in the side bar, you can see matching sources Turnitin has found in the Match Overview panel, starting with the most-used source.

As you can see from our example, because LSE coversheets accompany many student submissions, they can inflate the similarity score (accounting for 9% of the similarity score here). This illustrates how the % score of text matches within a report can be misleading and requires careful interpretation, which is why we recommend that no threshold similarity score is used to determine whether or not to consider a Turnitin report for academic misconduct.



Click on any of the matches in the Match Overview panel to reveal them within the student work.  This will generate a pop-up with the matched source, allowing a side-by-side comparison with the student text.

Other Matching Sources

Turnitin may match a source which is not the source where the student originally encountered the words. For instance, Turnitin may report a recent student essay as a match, when your student has read the words in an academic article. This is because the same text can appear in a number of different sources.

To view other matching sources, click on the arrow to the right of the matching source listed in the Match Overview panel.  Turnitin will display other matching sources where you may recognise one you put on a reading list or you are otherwise confident your students are likely to have read.


What do partial highlights mean?

Turnitin will often match a few phrases or words highlighted in a paragraph, like these:

Turnitin can only highlight the matched text, and can’t distinguish whether a student has:

  • copied words from a source into their notes, and then copied back into their work, forgetting these phrases weren’t their own words

  • tried to paraphrase a source, but not put it sufficiently into their own words

  • deliberately changed a few words in a passage to try to confuse the marker (and Turnitin)

Any of these offer an opportunity to begin a discussion about appropriate practice with the student.


Excluding Matches

Using the Filter tool to exclude matches

When you click on the Filter icon in the side bar, you will be able to see which parts of the submission have already been excluded from the similarity report (this will have been set up in the submission settings in Moodle). 

For example, Bibliography is excluded by default within Moodle. This has been done to make results more accurate, as bibliographies almost always match other sources, and can therefore inflate the extent to which a student’s work matches other sources.

Similarly, Quotes have been excluded by default.  This includes indented blocks of text and anything in quotation marks as these are the most common ways of quoting and citing in an essay. It is important to note that Turnitin does not recognise single quotation marks (‘…’).  You can learn more about excluding bibliography and quotes on Turnitin’s website.

Therefore, if Quotes have been excluded and passages have been highlighted, it might well be that these passages have been inadequately acknowledged by the student.

Within the report, in the Filter tool, you can further exclude matches under a certain percentage or word count. However, this needs to be carefully considered.  A low percentage match may seem insignificant in abstract but if the match is fully contained with a particular section, for example the conclusion, this may require investigation.

Excluding individual sources

By excluding certain sources, you can better focus on, potentially, more revealing matches within a student’s work. There are a number of occasions on which you might want to exclude sources:

  • When you feel sources are falsely inflating the matching score, as we saw above with the LSE coversheet.

  • Where a source is referenced by a student within the body of the essay, but the way the referencing is done is problematic (i.e. in the transcription of the quotation). In this case, the issue relates to the student's ability to properly quote and could be addressed by offering them training - see LSE Life’s offerings.

  • Where you know that the student erroneously submitted the assignment to another Moodle course before submitting to your course. This is known to happen and can result in a matching of score of 100% being given to student work. However, before excluding such matches you need to be confident that student has made a genuine mistake in previously submitting to another course.

Excluding sources is a straightforward process:

  • In the Match Overview panel, click on the arrow to the right of the matched source.  This will reveal a breakdown of all the matched sources in a new panel entitled Match Breakdown

  • Click on Exclude Sources at the bottom of the panel

  • Select the sources you wish to exclude by ticking the box next to each one

  • Click Exclude

You should see that the appropriate text is no longer highlighted and that the % score has been adjusted accordingly.

Restoring excluded sources

  • Click on the prohibited icon (excluded sources) in the side bar. This will open a new Excluded Sources panel.


  • Select the sources you wish to restore by ticking the box next to each one

  • Click Restore

You should see that the appropriate text is highlighted again and that the % score has been adjusted accordingly.

Academic judgement

If no text is highlighted, it doesn’t necessarily mean that there is no plagiarism. Turnitin is only a text-matching tool; it can’t tell if ideas or examples are original. In addition, we saw above that there are a number of sources with which it cannot match text. Your academic judgment is still the best tool for plagiarism detection.