What is plagiarism? In minor cases, it can be the quotation of a sentence or two, without quotation marks and without a citation (e.g., footnote) to the true author.

In the most serious cases, a significant fraction of the entire work was written by someone else: the plagiarist removes the true author(s) names(s) and substitutes the plagiarist's name, perhaps does some re-formatting of the text, then submits the work for credit (e.g., term paper or essay) or as part of the requirements for a degree (e.g., thesis or dissertation), or even as a professional/personal concern (e.g., article, blog entry, news item, etc.). 

Indicia of a quotation

When using another person's words, to avoid plagiarism one must always do both of the following:

1. provide a citation, either in the text or in a footnote, and
2. either enclose their words inside quotation marks or put their words in a block of indented, single-spaced text.

We define these two things as indicia of a quotation, for ease of reference in this writing. Plagiarism is the act of quoting material without including the indica of a quotation.

Note that the intent of a plagiarist is irrelevant. The act of quoting material without including the indicia of a quotation is sufficient to convict someone of plagiarism. It is no defense for the plagiarist to say "I forgot." or "It is only a rough draft." or "I did not know it was plagiarism."

Ideas too?

Some colleges and professional concerns have expanded the definition of plagiarism to include copying ideas without providing a citation to the original source. Perhaps the authorities that include ideas in their definition of plagiarism really intended to say that a close paraphrase of another author's work is plagiarism.

Paraphrasing without a citation is plagiarism

Suppose one reads a book by 'Smith' and encounters the short sentence: If the solution turns pink, it is worthless, and should be discarded.

 

It is plagiarism to paraphrase this sentence as:

 

When the liquid becomes light red, it is spoiled, and should be poured down the sink.

 

Note that most of the words have been changed, yet the sentence – in a very real way – has been copied. Copying, even with "original" alterations, can be copyright infringement. That is why such copying is also considered plagiarism.

 

The proper way to avoid such plagiarism is to cite the source in the text, or in a footnote, as in:

 

Smith [citation/footnote number] has reported that when the liquid becomes light red, it is spoiled, and should be poured down the sink.*

 

*No quotation marks are needed, because these are not Smith's exact words, but only a paraphrase. But a citation to Smith is still required.

Note that the short sentence by Smith is just a terse, contrived example for this essay, not an actual instance from plagiarized text. In most cases of this type of plagiarism, many sentences – probably whole paragraphs – will have been paraphrased.

Fine points of paraphrasing

One might wish to concisely summarize a long passage – a direct quotation would be too long. Hence, one paraphrases the original author.

One can properly write one paragraph that summarizes a book, published paper, opinion of a court, etc. using a paraphrase of the publication, with just one citation to that source at either the beginning or end of one's paragraph. The context makes it clear to the reader that one is describing someone else's publication. One should be careful not to include one's original thought(s) in a paragraph that is summarizing another person's thoughts, as such mixing could mislead the reader about the scope of one's work.

Note that the amount of citations is a matter of style. Some scholarly journals, particularly law reviews, sometimes have a footnote for each consecutive sentence, maybe even two footnotes attached at different places in one sentence. In such writing, a printed page can easily contain more space devoted to fine-print footnotes than to text. If these copious footnotes are to different sources, the page can be difficult to read, as full understanding may require the reader to consider all of the citations.

A proper paraphrase can even use a few isolated words from the original source without including quotation marks. When concisely summarizing a long passage, one also wants to summarize accurately, so using the identical – but isolated – words may be appropriate. In the above example, one might use Smith's word "pink" without quotation marks in the paraphrase. However, it is always essential to both (1) write text that makes clear that one is summarizing another's work and (2) cite the original source somewhere within the paragraph.

On the other hand, a string of several consecutive words copied verbatim from a source generally requires quotation marks. In making such judgments, one might consider the originality of the words. A common phrase (e.g., "obtained a writ of habeas corpus" in law, or "three degrees of freedom" in physics) is less deserving of quotation marks than genuinely original expression, since there may be few conventional alternatives for accurately expressing the same idea or fact.

These fine points may be dangerous for students, who would be well advised to use too many direct quotations, rather than paraphrasing. Again, the actual rules that apply to a student are given in the regulations of the student's college, or in instructions from the student's professor.

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