Preventing and Detecting Plagiarism

Varieties of Plagiarism

Overt plagiarism:

  • Turning in an entire paper acquired from a paper mill, another student, or from the Internet (often posted by another student or his/her professor).
  • Cutting and pasting together parts of essays from the Internet, informational Web sites, or electronic articles and books.
  • Knowingly failing to acknowledge the sources of ideas or quoted or paraphrased texts.

Inadvertent Plagiarism:

  • Sloppy handling of sources, resulting in faulty or inadequate citations.
  • Inappropriate collaboration.

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Why Students Plagiarize

  • They underestimate the time and effort required to find sources, read them, develop their ideas and write a paper, so they get caught with the due date imminent and too little time to complete the task legitimately.
  • They think it doesn't matter because (1) "everyone does it," (2) they don't recognize what research and writing contributes to what they learn from a course, or (3) they don't care if they learn anything as long as they get a good grade.
  • When they realize that they don't know how to do research, or interpret a text, or analyze the data, or do whatever the assignment requires, they're afraid to admit the problem and seek help.

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Preventing Plagiarism


  • Assume that students want to do the right thing and will if they know what that is and how to accomplish it.
  • Explain research and writing assignments thoroughly and discuss their role in helping students master the material.
  • Make sure students understand what plagiarism is (many think that if they change a few words the "paraphrase" need not be cited or that material found on a Web site is either "common knowledge" or common property, to be used at will). Have a clear statement regarding plagiarism in your syllabus and refer students to examples or administer tests of their understanding (Robert Harris's The Plagiarism Handbook has excellent examples of all of these and allows their use by faculty owning personal copies of the book.).
  • Discuss the function of documentation in furthering the "scholarly conversation."
    Involve the appropriate liaison librarian to help students learn research and citation skills.

But verify

  • Specify what kind of research is required, don't allow total free choice of topics, have students submit one or more preliminary stages of their research or writing, require that the bibliography be at least partially annotated (for example, to identify and discuss the most valuable sources used).
  • On the day papers are handed in, have students write a paragraph stating their thesis, major arguments, and the most important thing they learned from the doing the resesearch/writing the paper.
  • As you read the papers, be alert to such evidence of plagiarism as inappropriate topic or formatting, anachronistic references or anomalous diction/style in text, or dated sources in works cited. Some students fail to remove even the most obvious evidence that the text was purchased, originally written by another person, or assembled from unrelated parts.

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Tracking Down (Unacknowledged) Sources

  • If your suspicions are aroused:

    You can use Internet search engines such as Google or GoogleScholar to try to find the source document of odd terms or unexpected phrasing . Search using strings of 4-6 words as phrases (i.e., enclose them in quotation marks) and search several engines; they all index a different set of sites. See Additional Plagiarism Resources for Faculty.
  • Sometimes a student's works cited send up a flag. You can search authors' names on the web and in individual databases most likely to index articles on the subject of the paper or with OneSearch, which searches multiple databases at once.
  • Large portions of a paper may also be taken verbatim from online encyclopedias, journal collections, and other full-text databases. Many of these also allow you to search for strings of text enclosed in quotation marks. See Additional Plagiarism Resources for Faculty.
  • Check the free term paper sites, which are not indexed by the general web search engines (you have to search them individually). See Additional Plagiarism Resources for Faculty.
  • Question the student. Many, when asked to explain an unfamiliar word, phrase, concept, or argument will confess.
  • You can try one of the free, software-based "detectors," but these are not always highly reliable.
  • If you're very determined, you can check the fee-based web sites. Most will let you browse lists of topics or titles for free.

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