Why a Plagiarism “Score” can be Misleading

Molly Wright Starkweather, Kaplan University Tutor

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Recently on a social media group limited to online faculty members of various institutions, I read a post from a professor who had caught his student plagiarizing. While the post itself was pretty typical, stating how seeing a paper copied verbatim from another paper was making him lose faith in humanity, the comment thread exploded with unusual activity. An anonymous professor slammed the original poster with a series of comments that boiled down to one sentiment: “Shame on you for not failing the plagiarized paper immediately and wasting your time investigating the case in the first place.”

I believe in allowing for appeals in those grey area cases where a paper might not be as plagiarized as it seems. This might sound a little strange to those who have been trained to see either plagiarism or no plagiarism, so let us review the definition of plagiarism and see where there might actually be grey area, especially leading to circumstances where a paper might appear to be plagiarized but actually is not.

Plagiarism is defined by Kaplan University (2014) as “theft of someone else’s ideas or work” (para. 4). In many courses, students demonstrate mastery of skills by completing a research paper, which involves using the ideas and work of others in order to illustrate and explain the points the student is making in the central claim or thesis statement of the paper. The way academic writers distinguish the ideas or words of others from their own original ideas and words is by quotation marks, in-text citations, and reference page citations. In this way, students may incorporate the ideas and even the exact words of previously published sources that might also be paraphrased or also quoted directly by other students, all as part of an original academic discussion.

Many universities subscribe to plagiarism detection software that operates by comparing a student’s paper with all other papers in the software’s repository. Some software programs also can compare the papers with published academic sources and web sites as well. When a student’s work is copied word for word from a paper or a web site, it is very easy to see. The software generates a report on the amount of the paper that is considered unoriginal, or matching up with other papers, published sources, or web sites. At the beginning of the report is a “score” or percentage for how much of the submitted work has unoriginal material in it. The percentage does not prove or disprove the existence of plagiarism on its own, not even at 100%.

All research papers that incorporate outside sources and cite properly are going to generate a percentage on one of these reports. For Turnitin.com, many reports return a percentage of at least 10%. Why? Well, because the program will often count the reference page citations as part of the unoriginal material, even if the citation is perfect. This is why the term “plagiarism detector” needs to be read with an emphasis on “detector.” Programs like Turnitin do not prove plagiarism; they merely detect it. If students quote parts of passages once or twice, as they can do in an effective paper, even if those quotations are punctuated and cited perfectly, the quoted material and its citation will be flagged as unoriginal material. In an informative paper, that can bring the score up to 20%. If a student submits the same draft of a paper twice to Turnitin, it can be flagged as a 100% plagiarized paper, even though both submissions were written by the same student.

It is very important when investigating a potential case of plagiarism to review how the plagiarism detection software works and how false positives can be generated. For more on that, please visit the bottom right video resource on our Plagiarism Information Page titled “Understanding Turnitin Reports” (http://library.kaplan.edu/kuwc/plagiarisminfo). Feel free to share questions and thoughts about preventing plagiarism or plagiarism detection software in the comment area!



Kaplan University. (2014). Kaplan University’s plagiarism policy. Retrieved from https://kucampus.kaplan.edu/MyStudies/AcademicSupportCenter/WritingCenter/WritingReferenceLibrary/ResearchCitationAndPlagiarism/KaplanUniversitysPlagiarismPolicy.aspx


5 responses to “Why a Plagiarism “Score” can be Misleading

  1. Reblogged this on Empowered Composition and commented:
    Great explanation of the complexity involved in using plagiarism detection sites!

    • I thoroughly enjoy Empowered Composition, and I appreciate its mission. Thank you for sharing the piece! Preventing plagiarism as a default and not prosecuting as a default is something close to my heart. Cheers! ~Molly

  2. Thanks for covering this important topic, Molly! Walden uses Turnitin, and we always recommend that students and faculty review a report match by match instead of aiming for a specific percentage score.

    – Anne @ the Walden University Writing Center

  3. Wow. I didn’t know this. Thanks, Bill Ging

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