Wikipedia:Plagiarism

Plagiarism is the incorporation of someone else's work without providing adequate credit. While the terms are often confused, plagiarism and copyright infringement are not the same thing. Copyright infringement occurs when non-free content is used without permission in a way that violates the copyright holder's exclusive right; adequate credit does not efface infringement. Similarly, free content is plagiarized if used without acknowledging the source, even though there is no copyright issue.

Wikipedia's verifiability policy requires that articles be based on previously published sources. The sources must be cited appropriately to avoid the appearance of plagiarism, using inline citations that make clear where the text came from; and when quoting or paraphrasing very closely the careful use of in-text attribution may be required along with an inline citation. This guideline addresses when copying and close paraphrasing may not be a problem, how to avoid plagiarism when there is a risk, and how to address it when it is encountered.

Wikipedians are more vulnerable to accusations of plagiarism than are most writers, because we are required to stick closely to the reliable sources. For that reason, plagiarism concerns should be addressed calmly, with a view to educating rather than pointing the finger. The aim of plagiarism inquiries in most cases is simply to clean up the articles, rather than take action against the editor, except in the most serious of cases where the plagiarism is sustained and extensive.

Why plagiarism is a problem

Duplicating the work of others without credit, whether on purpose or by accident, brings both author and publisher into disrepute.

• A useful encyclopedia cites its sources so that readers can check the material for themselves.
• A credible encyclopedia does not silently present content copied from elsewhere as though it were original.
• The silent inclusion of copied content may pose legal problems for readers who re-use Wikipedia content, even if the text is "public domain" in the United States, which governs Wikipedia. Whether or not something is copyright-free in some country depends on the laws of individual countries.
• Subject matter experts may be discouraged from supporting or joining a project that fails to give credit to their work and that of their colleagues.

Definition of plagiarism

General definition

Further information: Intellectual property, Moral rights (copyright law), and Plagiarism

Plagiarism isn't identical to copyright infringement. Material from the public domain still needs to be attributed properly.

Merriam-Webster's Online Dictionary defines the act of plagiarizing a source as follows:

transitive verb:
1) to steal and pass off (the ideas or words of another) as one's own
2) use (another's production) without crediting the source.

Plagiarism is not always the same as copyright violation. If we copy word-for-word from a public-domain text, there is no copyright violation, but it is an act of plagiarism if we pass the work off as our own.

Forms of plagiarism on Wikipedia

Further information: Wikipedia:Citing sources and Wikipedia:Copyright

The problem of plagiarism on Wikipedia is unique, because no original research is allowed. Wikipedians are required to stick closely to reliable sources that support their edits, and in contentious topics this requirement is rigorously enforced. In addition, most articles are written by people with no specialist training in the topic, and with no academic or professional background in writing, editing, or researching. Plagiarism is therefore something that can easily happen inadvertently on Wikipedia, much more so than in any other form of publication, and all editors are strongly advised to look out for it in their own writing. It can take several forms:

• Inserting a text—copied word-for-word, or with very few changes—from a source that is not acknowledged anywhere in the article, either in the body of the article, or in footnotes, the references section, or the external links section.

• This is the most egregious form of plagiarism, and the least likely to be accidental.

• Inserting a text—copied word-for-word, or with very few changes—then citing the source somewhere in the article, but not directly after the sentence or passage that was copied.

• This can look as though the editor is trying to pass the text off as his own. It can happen by accident when inline citations are moved around during an edit, losing text-source integrity. It can also happen when editors rely on general references listed in a References section, without using inline citations.

• Inserting a text—copied word-for-word, or with very few changes—then citing the source in an inline citation after the passage that was copied.

• Here the editor is not trying to pass the work off as his own, but it is still regarded as plagiarism, because the source's words were used without in-text attribution. The more of the source's words that were copied, and the more distinctive the phrasing, the more serious the violation. Adding in-text attribution ("John Smith argues that ...") always avoids accusations of plagiarism. But be cautious when using it, because it can lead to other problems. For example, "According to Professor Susan Jones, human-caused increases in atmospheric carbon dioxide have led to global warming" would be a violation of NPOV, because this is the consensus of many scientists, not only a claim by Jones.

• Summarizing a source in your own words, but without clearly citing where you took the ideas from.

• Summarizing a source in your own words does not in itself mean you have not plagiarized, because you are still relying heavily on the work of another writer. To satisfy this guideline, the sourcing policy, and the policy on original research, credit should be given in the form of an inline citation after the phrase, sentence, or paragraph in question. See WP:CITE for how to write and place citations.

Where editors work with sources which are protected by copyright, these types of edits may also violate Wikipedia's copyright policy, a serious matter that is quite independent of any plagiarism concern.

How to avoid inadvertent plagiarism

• You can avoid plagiarism by summarizing source material in your own words, and by following:

• INCITE: Cite your sources in the form of an inline citation after the phrase, sentence, or paragraph in question. As a rule of thumb, if you use a work to help you write an article, cite it as a source. See WP:CITE for how to write citations.

• INTEXT: Use in-text attribution whenever you copy or closely paraphrase a source's words.

• INTEGRITY: Maintain text-source integrity by placing your inline citations in a way that makes clear which source supports which part of the text.

• When using a source's words, you can do it in the form of:

• direct speech—copying a source's words inside quotation marks, with in-text attribution and an inline citation. For example:

• John Smith wrote in The Times: "Cottage Cheese for Beginners is the most boring book I've ever read."

Note: the amount of text you quote from non-free sources must be limited to comply with non-free content policy.

• indirect speech—copying a source's words, or closely paraphrasing, without quotation marks; this also requires in-text attribution and an inline citation. For example:

• John Smith wrote in The Times that Cottage Cheese for Beginners was the most boring book he had ever read.

Note: even with in-text attribution, distinctive words or phrases may require quotation marks.

• Properly attributing any public-domain or free-content text you add to an article. See below for how to do that.

What is not plagiarism

See also: Wikipedia:When to cite

With some text, plagiarism is not a concern because content is not creative. Here are some examples where attribution is generally not required for plagiarism concerns, although you may still need to cite sources because of Wikipedia's policy on verifiability and original research:

• Use of common expressions and idioms, including those that are common in various sub-cultures such as academic ones.
• Phrases that are the simplest and most obvious way to present information. Sentences such as "John Smith was born on 2 February 1900" lack sufficient creativity to require attribution.
• Simple, non-creative lists of information, such as a list of song titles on an album, or actors appearing in a film. If creativity has gone into producing a list by selecting which facts are included, or in which order they are listed, then reproducing the list without attributing it to its source may constitute plagiarism.
• Mathematical and scientific formulae which are part of the general background knowledge of a field.
• Simple logical deductions.

Attributing text copied from other sources

Where text is not excluded from plagiarism concerns, Wikipedia requires clear attribution. An inline citation is frequently sufficient to attribute the source of information. Stronger attribution is required when content is copied or closely paraphrased from sources. This helps to maintain the clear distinction between work submitted by Wikipedia editors as their own work (which can be "edited mercilessly"), and work marked as a quotation (which must be properly credited and left essentially untouched). It also helps our reusers to distinguish when material is available under our dual licenses of CC-By-SA and GFDL, when it is available under CC-By-SA only, and when it may be non-free or public domain.

The handling of text varies according to whether or not the content has copyright restrictions that prevent Wikipedia's free use. The sections below detail the procedures. If an editor wishes to incorporate text from another source and is not sure which category the text falls into then they should ask on the talk page of the Wikipedia article or ask at Wikipedia:Reliable sources/Noticeboard before copying any text into a Wikipedia article. If it cannot be determined that the content is public domain or compatibly licensed, it must be presumed to be under copyright. Wikipedia's copyright policy notes: "Never use materials that infringe the copyrights of others. This could create legal liabilities and seriously hurt Wikipedia. If in doubt, write the content yourself, thereby creating a new copyrighted work which can be included in Wikipedia without trouble."

Note: works copied into Wikipedia must in all cases meet the Wikipedia core content policies: Wikipedia:Neutral point of view, Wikipedia:Verifiability and Wikipedia:No original research. Recommendations below pertain only to plagiarism concerns.

Close paraphrasing

Usually Wikipedia editors summarize sources, and as a rule the fewer the sources used to create the summary, the more difficult it can be to summarize a text accurately without plagiarising it. However providing the summary is made in good faith and the appropriate citations are given, then these issues are usually easy to resolve on the talk page of the article. See below for suggestions on how to deal with suspected plagiarism when no citations are given.

Sources under copyright

Further information: Wikipedia:Copyrights

Regardless of plagiarism concerns, works under copyright that are not available under a compatible free license require special handling to comply with copyright policy and non-free content policy and guideline. They cannot usually be extensively copied into Wikipedia articles. Limited amounts of text can be quoted if they are clearly indicated in the article with the use of quotation marks, or some other acceptable method (such as block quotations). All quotations must be followed by an inline citation. They cannot be closely paraphrased for copyright concerns, but must be substantially rewritten in original language.

Sources under copyleft

See also: Category:Attribution templates

If the external work is under a copyleft license that removes some restrictions on distributing copies and making modified versions of a work, it may be acceptable to include the text directly into a Wikipedia article providing the license is compatible with the CC-BY-SA and the terms of the license are met. (A partial table of license compatibility can be found at the Copyright FAQ). Most copyleft licenses require that author attribution is given, and, even if the license does not, the material must be attributed to avoid plagiarism. Attribution for copyleft licensed text is provided through the use of an appropriate attribution template, or similar annotation, which is usually placed in a "References section" near the bottom of the page.

Public-domain sources

See also: Category:Attribution templates

Whether copyright-expired or in the public domain for other reasons, material from public-domain sources is welcome on Wikipedia, but such material must be properly attributed.

The text may be attributed in the same way as it is for copyrighted material, but the source can also be copied directly into a Wikipedia article verbatim if it is cited and attributed through the use of an appropriate attribution template, or similar annotation, which is is usually placed in a "References section" near the bottom of the page (see the section "Where to place attribution" for more details).

A practice preferred by some Wikipedia editors, when copying in public-domain, or free content, verbatim, is to paste in the content in one edit, with indication in the edit summary of the source of the material. This practice has some advantages. This way, further changes such as modernizing language and correcting errors can be done in separate edits after the original insertion of text, allowing later editors the ability to make a clear comparison between the original source text and the current version in the article. If following this practice, in addition to the edit summary note, be sure to attribute the material either by using blockquotes or quotation marks, by using an attribution template, using an inline citation and/or adding your own note in the reference section of the article to indicate that language has been used verbatim. For an example of the latter, see the references section in planetary nomenclature [1], which uses a large amount of text from the Gazetteer of Planetary Nomenclature. (Whether adding text verbatim, summarizing, paraphrasing or making explicit quotations, regular referencing should be added to provide both attribution and verifiability.)

Public-domain attribution notices should not be removed from an article or simply replaced with inline citations unless it is verified that all phrasing and information from the public-domain source has been excised.

Copying within Wikipedia

Main page: Wikipedia:Copying within Wikipedia

Wikipedia's content is dually licensed under both the GFDL and CC-BY license models. Contributors continue to own copyright to their contributions, but liberally license it for reuse and modification. GFDL and CC-BY do require attribution. However, since Wikipedia's articles do not contain bylines, it is not necessary or appropriate to provide attribution on the article's face. As long as the licensing requirements for attribution are met (see the guideline for specifics), copying content from one Wikipedia article to another or from one language Wikipedia to another is not plagiarism.

Attributing media copied from other sources

See also: commons:Licensing and Wikipedia:Image use policy

For images and other media, you must specify correct source and licensing information, otherwise they run the risk of deletion. In particular, you should never use {{PD-self}}, {{GFDL-self}} or {{self}} if the image isn't yours. If the source requests a credit line, e.g. "NASA/JPL/MSSS", you should put one in the author field of {{information}}.

How to find plagiarism

Text plagiarism

There are a number of methods to detect plagiarism. Plagiarized text often demonstrates a sudden change of style and tone from an editor's usual style and may appear more advanced in grammar and vocabulary. Plagiarized material may contain unexplained acronyms or technical jargon that has been described in an earlier part of the plagiarized document. Because plagiarized material was written for other purposes, it is often slightly off topic, or un-encyclopedic in tone. An editor who plagiarizes multiple sources will appear to change writing style abruptly.

An easy way to test for plagiarism of online sources is to cut and paste passages into a search engine. Exact matches, or near matches, may be plagiarism. When running such tests, be aware that some other websites reuse content from Wikipedia. A list of identified websites which do so is maintained at Wikipedia:Mirrors and forks. It is usually possible to find the exact version in article history from which a mirror copy was made. Conversely, if the text in question was added in one large edit, and the text closely matches the external source, this is an indication of direct copying. If in doubt, double check search engine results with an experienced Wikipedian.

Another option is to utilize a plagiarism detector. Plagiarism detection systems, some of which are freely available online, exist primarily to help detect academic fraud. Some such programs and services can be found at Category:Plagiarism detectors. Wikipedia does not endorse, or recommend, any external services, so your own experience will be the guide.

It can also be useful to perform a direct comparison between cited sources and text within the article, to see if text has been plagiarized, including too-close paraphrasing of the original. Here it should be borne in mind that an occasional sentence in an article that bears a recognizable similarity to a sentence in a cited source is not generally a cause for concern. Some facts and opinions can only be expressed in so many ways, and still be the same fact, or opinion. A plagiarism concern arises when there is evidence of systematic copying of the diction of one or more sources across multiple sentences or paragraphs. In addition, if the source is not free, check to be sure that any duplicated creative expressions are marked as quotations.

Media plagiarism

Investigating media plagiarism can begin with a commonsense question: does it seem likely that the uploader is the original source? Sometimes the answer to this will be obvious. The person who scans an image from an 1825 textbook on herbs is unlikely to be the author, even if they have claimed {{PD-self}}. Sometimes doubts may be triggered by the professional quality of media, or by the exclusivity.

If you suspect plagiarism, try to locate the original source through an online search engine such as Google Image Search. Even if you don't locate a previously published original, plagiarism may still exist. Other factors to consider include the editing history of the uploader and, with images, image metadata, such as Exif and XMP.

Frequently a person who uploads and claims credit for another's image will leave the original image metadata, or a visible or invisible digital watermark, in place. If the author information conveyed by the metadata, or watermark, contradicts the author information on the image description page, this is a sign the image requires investigation. A user's original photographs can also be expected to have similar metadata, since most people own a small number of cameras; varied metadata is suspicious. Suspicions based on metadata should be checked with other editors experienced with images and other media.

How to respond to plagiarism

Copyright violations

Main page: Wikipedia:Copyright violations

See also: Wikipedia:Copyright problems, Wikipedia:Possibly unfree images, and Wikipedia:Guide to image deletion

If you find duplicated text, or media, consider first whether the primary problem is plagiarism, or copyright infringement. If the source is not public domain, or licensed compatibly with Wikipedia, or if you suspect that it is not, you should address it under the copyright policies.

Addressing the editor involved

If you find an example of plagiarism, where an editor has copied text, media, or figures, into Wikipedia without proper attribution, contact the editor responsible, point them politely to this guideline page and ask them to provide the proper attribution. Please use care to frame concerns in an appropriate way, as an accusation of plagiarism is a serious charge. Even in blatant, conspicuous cases, it is important to remain civil. Given that attribution errors may be inadvertent, intentional plagiarism should not be presumed in the absence of strong evidence. Remember that contributors may not be familiar with the concept of plagiarism, or that their definition may differ from that adopted by Wikipedia. Remember to start with the assumption of good faith. It may also be helpful to politely refer them to Wikipedia:Verifiability, Wikipedia:Citing sources, and/or Help:Citations quick reference. Editors who have difficulties, or questions, about this guidance can be referred to the Help Desk, or media copyright questions.

In addition to requesting repair of the first instance, you may wish to invite the editor to identify and repair any other instances of plagiarism they may have placed prior to becoming familiar with our guideline.

If you find that an editor persists in plagiarising others' work after being notified of this guideline, report him, or her, at the administrators' noticeboard so that an administrator can respond to the issue. Be sure to include diffs which show both the plagiarism and warnings which were given and ignored.

Repairing plagiarism

It may not always be feasible to contact the contributor. For example, an IP editor who placed text three years ago and has not edited since is unlikely to be available to respond to your concerns. Whether you are able to contact the contributor or not, you can also change the copied material, or provide the attribution, or source on your own. Material that is plagiarized but which does not violate copyright does not need to be removed from Wikipedia if it can be repaired. Add appropriate source information to the article or file page, wherever possible. With text, you might move unsourced material to an article's talk page until sources can be found.

Where to place attribution

If a Wikipedia article is largely constructed through summarizing reliable sources, but there is a paragraph or a few sentences copied from compatibly licensed or public-domain text which is not placed within quotations, then putting an attribution in a footnote at the end of the sentences or paragraph is sufficient, although it does not preclude supplementing that with the method described below. To aid with attribution at the end of a few sentences consider using the {{citation-attribution}} template, or source specific ones such as {{DNB}}. Directions for usage are provided at the templates.

If a significant proportion of the text is legally copied from another source, then attribution for compatibly licensed and public-domain text is generally provided either through the use of an appropriate attribution template, or similar annotation, placed in a "References section" near the bottom of the page.

In such cases consider adding the attribution statements at the end of the Reference section directly under a line consisting of Attribution in bold:

Attribution

Place appropriate attribution template, or similar annotation here

See for examples Western Allied invasion of Germany and the Battle of Camp Hill.

See also

• Wikipedia:Quotations (essay)
• Wikipedia:Close paraphrasing (essay)
• Wikipedia:Copy-paste (summary of policies and practises)
• Wikipedia:Wikipedia Signpost/2009-04-13/Dispatches – Wikipedia Signpost article on plagiarism

Further reading

Articles, books, and journals

• Eisner, Caroline, and Martha Vicinus, eds. Originality, Imitation, and Plagiarism: Teaching Writing in the Digital Age. Ann Arbor: University of Michigan Press (Digitalculturebooks), 2008. Print. ISBN 9780472070343 (cloth). ISBN 9780472050345 (paper). "Originality, Imitation, and Plagiarism: About the Book". University of Michigan Press, 2008. Web. 12 Mar. 2009. ("This collection is a timely intervention in national debates about what constitutes original or plagiarized writing in the digital age.")

• Jaschick, Scott. "Winning Hearts and Minds in War on Plagiarism". Inside Higher Ed 7 Apr. 2008. InsideHigherEd.com, ©2009. Web. 12 Mar. 2009.

• Plagiary: Cross-Disciplinary Journal in Plagiarism, Fabrication, and Falsification. Ed. John P. Lesko (Saginaw Valley State University). Scholarly Publishing Office, University Library, University of Michigan, 2006–2008. Web. 12 Mar. 2009. ISSN 1559-3096. ("Publication of the Scholarly Publishing Office, University of Michigan Copyright Plagiary.org 2005–2008")

Digital academic resources

• Cornell University. "Recognizing and Avoiding Plagiarism". College of Arts and Sciences, Cornell University, ©2005. Web. 12 Mar. 2009.

• Duke University Libraries. "Citing Sources: Documentation Guidelines for Citing Sources and Avoiding Plagiarism". Duke University Libraries, (last modified) 2 June 2008. Web. 12 Mar. 2009. (Provides hyperlinked "Citation Guides" pertaining to the most commonly-used citation guidelines, including parenthetical referencing; includes: APA, Chicago, CSE, MLA, and Turabian style guidelines; such style guides define plagiarism and how to avoid it.)

• Harvard College Library. "Research Guides". Harvard University Library, (last reviewed) 9 March 2009. Web. 12 Mar. 2009. (Compiled by the Staff of Harvard College Library.)

• Indiana University at Bloomington. "Plagiarism: What It is and How to Recognize and Avoid It". Writing Tutorial Services, Campus Writing Program, Indiana University, (last updated) 27 Apr. 2004. Web. 12 Mar. 2009.

• University of New South Wales. "Avoiding Plagiarism". The Learning Centre, Academic Skills Resources, University of New South Wales, (last updated) 24 Oct. 2008. 12 Mar. 2009. (Includes: "What Is Plagiarism?"; "Common Forms of Plagiarism"; and "Plagiarism & the Internet".)

External links

• FamousPlagiarists.com – Website published by John P. Lesko, associate professor of English at Saginaw Valley State University; editor of Plagiary (see "Further reading"). (Hyperlinked resources, including: a "glossary of terms" relating to plagiarism; a bibliography of "Books and Other Resources"; and profiles of "Famous Plagiarists". "Copyright 2004-2006 Famous Plagiarists.com / War On Plagiarism.org. Some Rights Reserved").
• The Plagiarism Checker – Facility for detecting student plagiarism at dustball.com. ("EDUC478: This educational software was designed as a project for the University of Maryland at College Park Department of Education." © Copyright 2002 by Brian Klug.)
• Plagiarism.org – By Turnitin (cited by Eisner and Vicinus [below]).
• "Read a Q&A with the editors on Inside Higher Education" – Interview with Caroline Eisner and Martha Vicinus, editors of Originality, Imitation, and Plagiarism, conducted on 3 Apr. 2008.