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Plagiarism and Citation

This guide provides information on how to properly cite your sources and avoid plagiarism.

The Purpose of Citation

Source citation in research: 

  • Gives credit to the original author
  • Demonstrates to the reader that the writer has done the appropriate background research
  • A method of participating in scholarly communication
  • Avoids plagiarism of copyrighted materials
  • Provides readers with links to additional information resources


"Plagiarism is the act of presenting the words, ideas, or images of another as your own; it denies authors or creators of content the credit they are due. Whether deliberate or unintentional, plagiarism violates ethical standards in scholarship” (see APA Ethics Code Standard 8.11, Plagiarism). 

CGHS Defines Plagiarism 

Plagiarism is the presentation of another’s work as if it were one’s original. Proper and complete citation and reference, in accordance with APA style guidelines, is required of all student work. Specific examples of plagiarism include:

  • Cutting and pasting or re-entering information from another’s work into a document without correct citation or attribution
  • Information is attributed to a source other than the original
  • Material authored by someone else is submitted as original work
  • Turning in previously prepared work, in part or in whole, is considered self-plagiarism and is unacceptable. In instances where it may be appropriate to include prior work, the student must obtain permission from the instructor to include the prior work.
  • Information is properly cited but the paraphrasing is not substantively different from the original source
  • Infrequent or missing citations

Types of Plagiarism

Plagiarism is the presentation of another’s work as if it were one’s original work. This includes both deliberate and accidental acts. The following are some of the major common types.

Direct Plagiarism Copying work exactly without citation and presenting it as original
Self Plagiarism Re-submitting or re-using your own previously published or submitted work without permission or notice
Paraphrasing Plagiarism Copying work and making minor changes without citation and presenting it as original
Patchwork Plagiarism Copying work and interspersing it with original work but presenting it all as original
Accidental Plagiarism Failure to properly cite or paraphrase
Bad Attribution Failure to correctly attribute work - mislabeling the actual authors or creators

Avoiding Plagiarism


  • Can’t I avoid problems just by listing every source in the bibliography? No, you need to integrate your acknowledgements into what you’re saying. Give the reference as soon as you’ve mentioned the idea you’re using, not just at the end of the paragraph. It’s often a good idea to name the authors (“X says” and “Y argues against X,”) and then indicate your own stand (“A more inclusive perspective, however, . . . “). The examples in this file and the one on Standard Documentation Formats show various wordings. Have a look at journal articles in your discipline to see how they refer to their sources.

  • If I put the ideas into my own words, do I still have to clog up my pages with all those names and numbers? Sorry—yes, you do. In academic papers, you need to keep mentioning authors and pages and dates to show how your ideas are related to those of the experts. It’s sensible to use your own words because that saves space and lets you connect ideas smoothly. But whether you quote a passage directly in quotation marks, paraphrase it closely in your own words, or just summarize it rapidly, you need to identify the source then and there. (That applies to Internet sources too: you still need author and date as well as title and URL.  The handout Standard Documentation Formats gives examples for a range of types.)

  • But I didn’t know anything about the subject until I started this paper. Do I have to give an acknowledgement for every point I make? You’re safer to over-reference than to skimp. But you can cut down the clutter by recognizing that some ideas are “common knowledge” in the field—that is, taken for granted by people knowledgeable about the topic. Facts easily found in standard reference books are considered common knowledge: the date of the Armistice for World War I, for example, or the present population of Canada. You don’t need to name a specific source for them, even if you learned them only when doing your research. In some disciplines, information covered in class lectures doesn’t need acknowledgement. Some interpretive ideas may also be so well accepted that they don’t need referencing: that Picasso is a distinguished modernist painter, for instance, or that smoking is harmful to health. Check with your professor or TA if you’re in doubt whether a specific point is considered common knowledge in your field.

  • How can I tell what’s my own idea and what has come from somebody else? Careful record-keeping helps. Always write down the author, title and publication information (including the specific identifying information for online publications) so you can attach names and dates to specific ideas. Taking good notes is also essential. Don’t paste passages from online sources into your draft: that’s asking for trouble. As you read any text—online or on the page—summarize useful points in your own words. If you record a phrase or sentence you might want to quote, put quotation marks around it in your notes to remind yourself that you’re copying the author’s exact words, whether electronically or in handwriting. If you record a distinctive phrase or sentence you might want to quote, put quotation marks around it in your notes to remind yourself that you’re copying the author’s exact words. And make a deliberate effort as you read to notice connections among ideas, especially contrasts and disagreements, and also to jot down questions or thoughts of your own. If you find as you write that you’re following one or two of your sources too closely, deliberately look back in your notes for other sources that take different views; then write about the differences and why they exist. See the advice file Taking Notes from Research Reading for more tips. 
  • So what exactly do I have to document? With experience reading academic prose, you’ll soon get used to the ways writers in your field refer to their sources. Here are the main times you should give acknowledgements. (You’ll notice many different formats in these examples. See the file on Standard Documentation Formats for advice on these systems.)

    • Quotations, paraphrases, or summaries: If you use the author’s exact words, enclose them in quotation marks, or indent passages of more than four lines. (For more on the mechanics of quoting, visit our file on using quotations.) But it’s seldom worthwhile to use long quotations. In literary studies, quote a few words of the work you’re analysing and comment on them. In other disciplines, quote only when the original words are especially memorable. In most cases, use your own words to paraphrase or summarize the idea you want to discuss, emphasizing the points relevant to your argument. But be sure to name sources even when you are not using the exact original words. As in the examples below, it’s often a good idea to mention the author’s name. Mentioning the author’s name indicates where the borrowing starts and stops and gains you some reflected glory for responding to the experts.

      • e.g. As Morris puts it in The Human Zoo (1983), “we can always be sure that today’s daring innovation will be tomorrow’s respectability” (p. 189). [APA system]
      • e.g. Northrop Frye discusses comedy in terms of the spring spirit, which he defines as the infusion of new life and hope into human awareness of universal problems (Anatomy 163). The ending of The Tempest fits this pattern. [MLA system—short title to distinguish among different works by same author].
    • Specific facts used as evidence for your argument or interpretation: First consider whether the facts you’re mentioning are “common knowledge” according to the definition in point 3 above; if so, you may not need to give a reference. But when you’re relying on facts that might be disputed within your discipline—perhaps newly published data—establish that they’re trustworthy by showing that you got them from an authoritative source.
      • e.g. In September 1914, more than 1300 skirmishes were recorded on the Western Front.8 [traditional endnote/footnote system]
      • e.g. Other recent researchers (4, 11, 12) confirm the findings that drug treatment has little effect in the treatment of pancreatic pseudocysts. [numbered-note system for biomedical sciences]
    • Distinctive or authoritative ideas, whether you agree with them or not: The way you introduce a reference can indicate your attitude and lead into your own argument.
      • e.g. Writing in 1966, Ramsay Cook asserted that Canada was in a period of critical instability (174). That period is not yet over, judging by the same criteria of electoral changeability, economic uncertainty, and confusion in policy decisions. [new MLA system]
      • e.g. One writer (Von Daniken, 1970) even argues that the Great Pyramid was built for the practical purpose of guiding navigation. [APA system]

From the University of Toronto Writing Advice Website