The relationship between a similarity score and plagiarism is often misunderstood. Many assume that a high similarity score automatically signifies plagiarism, but that is not always the case. The Similarity Report is a valuable tool for educators, but its primary function is to highlight matching content from other sources. The percentage shown in the report reflects how much a student’s work matches other content in Turnitin’s databases that the instructor selects for the assignment. This could include sources from the internet, academic publications, and other student papers. Determining whether plagiarism has occurred requires more than looking at the score.
- Interpreting a similarity score correctly requires an understanding of the context in which the student’s work was produced. For instance, a high similarity score may result from improperly cited quotes or references. On the other hand, a low score does not guarantee the absence of plagiarism. For example, a student might engage in contract cheating or use ‘content spinners’, leading to a low similarity score despite the work not being original. Educators should consider the broader context surrounding the student’s work to make informed judgments about academic integrity.
Several factors can influence the percentage displayed in a Similarity Report, including but no limited to:
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Longer assignments tend to have higher similarity scores due to the larger volume of text.
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The nature of some assignments (like research papers or literature reviews with high levels of quotes and citations) will naturally yield higher scores.
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Students who are new to academic writing may struggle with correct citation or paraphrasing practices, leading to unintentional plagiarism.
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Genre and task expectation also have an impact on whether text similarity is expected in a submission.
See the article,
Similarity in the Classroom for information on how educators can use the Turnitin Similarity Report to meet instructional goals and how to best utilize a similarity score.