Answered By: Ashley Librarian
Last Updated: Oct 14, 2020     Views: 28529

Faculty often ask what percentage is acceptable for plagiarism after students run their paper through Grammarly.

After running a plagiarism check on your document, Grammarly displays percentage that tells you how much of the document was identified as possible plagiarized content.  Grammarly is not confirming plagiarism has occurred, but it is scanning the free web for text that matches the document submitted through Grammarly.

It is important to note that Grammarly is not able to tell if the student appropriately used an in-text citation to say where the information came from.

Look at the examples below to see how Grammarly has :

  • Text that was cited correctly
  • Text that was cited, but identified as plagiarism from CourseHero
  • Text that was plagiarized
  • Text that was identified as plagiarism but is a false positive

After reviewing these examples you will see why it isn't advisable to set a percentage that students must meet.  A student's document may show 35% plagiarized, but after review, you can see that they correctly used in-text citations to document where the information came from.  On the other hand, a student's work may only show 8% plagiarize but that entire passage is copy and pasted from a website with no attribution.

This first example shows a student has quoted information taken from the American Academy of Family Physicians (AAFP) and has correctly cited it using a parenthetical citation. Grammarly has identified this as a text match and we can see the website it says the information came from is the same as what the student has identified (AAFP).



This next example shows a scenario where a student has used information from a source and cited it in-text, however, Grammarly is identifying this as a text match with content from Course Hero. 

CourseHero describes themselves as an "online learning platform" where students can share study resources.  The service requires a fee or students have the option of uploading their own work in return for access to the study resources.  These study resources include examples of student work for specific courses at institutions.

In the example below, Grammarly has identified that the text matches text in CourseHero, which means:

  • The student copied the text from another student's work that was uploaded to CourseHero, or
  • The student used information from the (Prater, 2014) source and Grammarly has shown only the first text match (CourseHero) and is not showing a match for the original website, which can be found with some basic Google searching:

In an instance like this, a faculty member would want to examine the References list to see if the student correctly provided information for the original source (which technically could've also been copied from Course Hero).  It is not possible to say with certainty that this is plagiarized work.


The next example shows us where a student has taken text directly from a source and has not attempted to provide attribution and can be considered plagiarism.


Finally, this example shows a false positive. Grammarly has identified part of a sentence as being plagiarized, however, the words are very common and it is not considered plagiarism.

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