Adapted from the ninth edition of the MLA Handbook. Read an adapted version of the guidelines in Spanish.

Occasionally an author or public speaker is accused of plagiarism. No doubt you have had classroom conversations about plagiarism and academic dis­honesty. Your school may have an honor code that addresses academic dis­honesty; your school almost certainly has disciplinary procedures meant to address plagiarism. But you may not be sure what exactly this offense is and how to avoid committing it.

What Plagiarism Is and Why It’s a Serious Matter

Plagiarism is presenting another person’s ideas, words, or entire work as your own. Plagiarism may sometimes have legal repercussions (e.g., when it involves copyright infringement) but is always unethical.

Plagiarism can take a number of forms. Copying a published or unpub­lished text of any length, whether deliberately or accidentally, is plagiarism if you don’t give credit to the source. Paraphrasing someone’s ideas or argu­ments or copying someone’s unique wording without giving proper credit is plagiarism. Turning in a paper or thesis written by someone else, even if you paid for it, is plagiarism.

It’s even possible to plagiarize yourself. In published work, if you reuse ideas or phrases that you used in prior work and do not cite your prior work, you have plagiarized. Many schools’ academic honesty policies prohibit the reuse of one’s prior work in papers, theses, and dissertations, even with self-citation. (Sometimes, however, revising and building on your earlier work is useful and productive for intellectual growth; if you want to reuse portions of your previously written work in an educational context, ask your instructor.)

When writers and public speakers are exposed as plagiarists in profes­sional contexts, they may lose their jobs and are certain to suffer public embarrassment, diminished prestige, and loss of credibility. One instance of plagiarism can cast a shadow across an entire career because plagiarism reflects poorly on a person’s judgment, integrity, and honesty and calls into question everything about that person’s work. The consequences of plagia­rism aren’t just personal, however. The damage done is also social. Ulti­mately, plagiarism is serious because it erodes public trust in information.

Avoiding Plagiarism

Careful Research

Many instances of unintentional plagiarism can be traced back to sloppily taken notes during the research process. So be scrupulous in your research and note-taking. When you write, your notes will help you identify all bor­rowed material. Make sure that you clearly identify when you are copying words from a source (and transcribe them exactly or retain digital images of the passages), when you are summarizing or paraphrasing a source, and when you are jotting down an original thought of your own. Remem­ber to record page numbers for quotations and paraphrased passages in your notes. Note-taking apps can help you collect information about your sources and organize your own ideas.

Steer a middle course between recording too much information and too little. Details, like specific phrases and passages, will help you present evidence in your paper. But also remember to describe in your notes how a writer used those details to arrive at a particular conclusion. Notes that merely list quotations without giving any sense of why they are important, how they relate to the sources they derive from and to one another, and what they collectively mean will be of little help to you once you start writing.

As you do research, collect all the sources you use in one place, which will allow you to double-check that your work acknowledges them. Care needs to be taken even when using a digital reference manager for note-taking or creating documentation, since the data used by the software can be incorrect and must be checked against your source. Thus, manual input is often required. Citation tools are a good starting point, but their output must be verified and edited.

For more on conducting research and on the methods and tools that can help you, see the MLA Guide to Undergraduate Research in Literature, the MLA Guide to Digital Literacy, the free tutorials on using the MLA Inter­national Bibliography, and the bibliography’s free online course.

Giving Credit

Once you’ve carefully tracked your research, avoiding plagiarism is rela­tively straightforward: when the work of others informs your ideas, give credit by summarizing or paraphrasing that work or by accurately quoting it—and always cite your source. Think of citation as an act of generosity to those whose ideas you share and to your reader, and not as something done to avoid being penalized for a mistake.

Giving Credit by Paraphrasing

Paraphrasing allows you to maintain your voice while demonstrating that you understand the source because you can restate its points in your own words and with your own sentence structure.

Paraphrase from a source when you want to condense or summarize long passages, arguments, or ideas; make your writing more concise; stay in con­trol of your ideas and argument and maintain your voice; or signal your knowledge of key lines of conversation and concepts from your sources.

Giving Credit by Quoting

Quoting can be effective when someone else’s words are the focus of analy­sis or perfectly express an idea. Quotations are most effective in research-based writing when used selectively. Quote only words, phrases, lines, and passages that are particularly apt, and keep all quotations as brief as pos­sible. Always explain the relevance of the quotation to your point. Your project should be about your own ideas, and quotations should help you explain or illustrate those ideas and how you arrived at them.

Quote from a source when the exact wording is important to your claim, the phrasing is particularly compelling, or you want to focus on the lan­guage in the source. Quotations should not be used as a substitute for summarizing or paraphrasing ideas you do not fully understand.

Giving Credit by Citing Sources

When you paraphrase and quote sources, it’s important to cite your sources in the text and create a corresponding works-cited-list entry. Detailed explanations of how to paraphrase and quote sources, create works-cited-list entries, and use in-text citations appear in chapters 4, 5, and 6 of the ninth edition of the MLA Handbook.

When Documentation Is Not Needed

Documentation is required for any work that you quote from or paraphrase; that you refer to substantively, whether the reference is to a specific place in the source (a page, a chapter) or to the source as a whole; or that you acknowledge as the source of facts you provide or ideas you formulate. But documentation is not required for common knowledge, passing mentions, or allusions.