Wikipedia:Plagiarism

This guideline addresses how to avoid plagiarism on Wikipedia and how to address it when it is encountered.

Plagiarism is the incorporation of someone else's work without providing adequate credit.

If an external work is under a standard copyright notice, then copying text from such a work, with little or no alteration to that work, into a Wikipedia article is usually a copyright violation, unless it is clearly indicated in the text by quotation marks or some other acceptable method (such as block quotations).

If the external work is under a copyleft licence which remove some restrictions on distributing copies and modified versions of a work, it may be acceptable to include the text directly into a Wikipedia article providing adequate attribution is provided, but it depends on the specific licence. Most copyleft licences require that the attribution is given, and even if it is not, most articles in Wikipedia that are derived from such external works attribute the text to the source. Due to licencing incompatibility between the licence of some copyleft sources and the Wikipedia content licence—for example some licences do not allow commercial redistribution—text from such works must be treated as if the text were under the standard copyright notice, if in doubt ask on the talk page of the Wikipedia article, or ask at Wikipedia:Reliable sources/Noticeboard before copying any text into a Wikipedia article.

Some external works that are copyright expired have been copied into Wikipedia, and although there is no legal requirement to include attribution, most articles in Wikipedia that are derived from such external works attribute the text to the copyright expired source.

If the external work is copyright expired, but contains an original idea, or is a primary source, then it may be necessary to alter the wording of the text (for example not including all the text from the original work, or quoting some sections, or specifically attributing to a specific source an opinion included in the text,) to meet the Wikipedia content policies of neutral point of view and Wikipedia:no original research (in particular the restrictions on the use of primary sources).

Attribution for copyleft licenced text and copyright expired text are attributed 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.

An accusation of plagiarism is very serious. When dealing with plagiarism, take care to address the issue calmly and civilly. Focus on concerns about proper sourcing to give due credit.

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

Whether it is the result of deliberate deception or improper attribution, duplicating the work of others without credit can bring both author and publisher into disrepute.

You can avoid any dispute concerning potential plagiarism by:

• rewriting text completely into your own words, using multiple referenced sources;
• marking any material you copy as a verbatim quote, using quotation marks, and referencing the source;
• properly attributing any public-domain or free-content text that you place directly into an article.

Why plagiarism is a problem

• A useful encyclopedia cites the sources of its content, so that readers may verify the information or seek further information from the source.

• A credible encyclopedia must not silently present content copied from elsewhere as though it were original.

• The correction of improperly copied content disrupts the encyclopedia and may require the deletion of all subsequent edits to the article.

• 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 participating in (or endorsing) a project which fails to give proper credit to their work and the work of their colleagues.

What is not plagiarism

See also: Wikipedia:When to cite

This section deals with situations where plagiarism is not a concern (although, if the source is not free, copyright infringement may still be an issue in some of these situations). However you may still need to cite sources because of Wikipeda's policy on verifiability.

Here are some examples where attribution is generally not required:

• Use of common expressions and idioms, including those that are common in various sub-cultures such as academic ones. In order to qualify as a "common expression or idiom":
  • the phrase must have be used without attribution at least 2 years ago by someone other than the originator and in a reliable source, in other words one that is likely to have watchful editors and lawyers.
  • there must be no evidence that the author(s) or publisher(s) of the unattributed use later lost or settled out of court a lawsuit based on the unattributed use, and that the publisher did not issue an apology or retraction for plagiarism relating to the the unattributed use. Since it is impossible to prove completely that something does not exist, Wikipedia editors who suspect plagiarism is involved must provide reliable evidence of such a legal judgement, out-of-court settlement, apology or retraction.
• Phrases that are the simplest and most obvious way to present information. Editors who claim that the phrasing at issue is plagiarism must show that there is an alternative phrasing that does not make the passage more difficult to read. If a proposed rephrasing may impair the clarity or flow of a paragraph, they must propose a rephrasing that avoids such side-effects, possibly by rephrasing content preceding and following the disputed passage or even the whole paragraph. An objective measure of whether a proposed rephrasing makes the passage more difficult to read can be obtained by a readability tool such as Dispenser's Readability Analyser. However issues about clarity and flow will have to be resolved by discussion.
• Definitions of terms, theories, hypotheses, etc. In these cases accuracy and avoidance of original research take priority. However the attribution may be advisable for other reasons, for example new definitions, hypotheses, etc. may not yet be consensus in the relevant fields, and unattributed use often implies that quoted or paraphrased content is the mainstream view (see Wikipedia's policies on undue weight and neutral point of view).
• 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 the 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. In any case such judgements, if not supported by a citation, may violate Wikipedia's ban on original research – for example in a cast list, decisions about which roles are major and which are minor or totally unimportant. U.S.A. law on such lists is illustrated by the case Feist Publications v. Rural Telephone Service.
• Mathematical and scientific formulae which are part of the general background knowledge of a field. More complex formulae will require a citation anyway, because of Wikipeda's policy on verifiability.
• Simple logical deductions. Complex logical deductions, in contrast, generally require a citation, because of Wikipeda's policy on verifiability.

Attributing text copied from other sources

Wikipedia draws clear distinctions 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). In quotations, editorial notes and minor changes are sometimes useful, but must be clearly marked as such. See WP:MOSQUOTE for details.

• copyright restrictions. Works with copyright restrictions can not usually be copied into Wikipedia articles. Limited amounts of text can be copied from from such works providing they meet copyright restrictions, and 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 (see WP:PROVEIT).

• works free of copyright restrictions The sections below detail some cases where in some circumstances works may be copied from some sources directly into a Wikipedia article without the restrictions placed upon copying copyrighted material. However if is considered morally correct to attribute such works to the original author or publications as detailed in the sections below. Additions of this kind can be improved through the normal process of wiki editing.

• If not sure ask for help. If an editor wishes to incorporate text from another source and is not sure which category the text fall 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.

• Compliance with the content policies. It is not enough for works copied into Wikipedia to meet copyright and restrictions on plagiarism described on this page, they must also meet all the Wikipedia content policies (WP:NPOV WP:V WP:NOR).

Sources under copyright

If an external work is under a standard copyright notice, then copying text from such a work, with little or no alteration to that work, into a Wikipedia article is usually a copyright violation, unless it is clearly indicated in the text by quotation marks or some other acceptable method (such as block quotations).

As a rule of thumb if an editor uses a work to help write an article then that source should cited, as not to do so to do so could be seen as introducing original research into an article. This is particularly true if opinions or analysis of events are added to an article.

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 sort out 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 copyleft

See also: Category:Attribution templates

If the external work is under a copyleft licence which remove some restrictions on distributing copies and modified versions of a work, it may be acceptable to include the text directly into a Wikipedia article providing adequate attribution is provided, but it depends on the specific licence. Most copyleft licences require that the attribution is given, and even if it is not, most articles in Wikipedia that are derived from such external works attribute the text to the source. Due to licencing incompatibility between the licence of some copyleft sources and the Wikipedia content licence—for example some licences do not allow commercial redistribution—text from such works must be treated as if the text were under the standard copyright notice, if in doubt ask on the talk page of the Wikipedia article, or ask at Wikipedia:Reliable sources/Noticeboard before copying any text into a Wikipedia article.

Some authors explicitly release their work under a free license. If the license of the material is compatible with the CC-BY-SA, then it can in most cases be added directly to articles on Wikipedia. However, "free" license does not mean free of copyright concerns. The licensing requirements must be met.

For example, Wikipedia's contributors retain copyright to material they contribute here, though CC-BY-SA and GFDL allow reuse and modification with proper attribution provided that reusers do not attempt to impose additional restrictions, but release modifications under one or the other of those licenses (if copying within Wikipedia, both).

In all cases, the moral rights of the original authors whose works are copied must be respected during the term of their rights.

Attribution for copyleft licenced text are attributed 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

Material from public domain and free sources is welcome on Wikipedia, but such material must be properly attributed.

The text may be treated as copyright material in which case attribution should be made in the same way as it is for copyrighted material. But the source can also be copied directly into a Wikipedia article verbatim providing it meets the Wikipedia content policies. If this is done then be sure to cite the source, and attribute the work 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.

If the external work is in the public domain, but contains an original idea, or is a primary source, then it may be necessary to alter the wording of the text (for example not including all the text from the original work, or quoting some sections, or specifically attributing to a specific source an opinion included in the text,) to meet the Wikipedia content policies of neutral point of view and Wikipedia:no original research (in particular the restrictions on the use of primary sources).

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.

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.

Copyright expired sources

See also: Category:Attribution templates

Some external works that are copyright expired have been copied into Wikipedia, and although there is no legal requirement to include attribution, most articles in Wikipedia that are derived from such external works attribute the text to the copyright expired source.

If the external work is copyright expired, but contains an original idea, or is a primary source, then it may be necessary to alter the wording of the text (for example not including all the text from the original work, or quoting some sections, or specifically attributing to a specific source an opinion included in the text,) to meet the Wikipedia content policies of neutral point of view and Wikipedia:no original research (in particular the restrictions on the use of primary sources).

Attribution for copyleft licenced text and copyright expired text are attributed 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.

Generating articles from other sources

In the past, Wikipedia has undertaken large projects in which many articles are generated from copyright expired and other public domain or copyleft sources. For instance, Encyclopaedia Britannica 1911 was used as a source to build many articles in 2002. These articles were marked with the {{1911}} template to make it clear that text had been taken from this source. Similar templates for other free content can be found at Category:Attribution templates. These templates are an accepted way to give credit to free content when that free content is used to build Wikipedia. Additions of this kind can be improved through the normal process of wiki editing.

Before engaging in any similar large-scale project of your own, be sure to discuss your ideas at Wikipedia:Village pump (proposals) and/or a relevant Wikiproject. Mass edits of this kind should always be discussed in advance to be sure that you are properly attributing your sources.

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.

Language translations between various Wikimedia Foundation wikis are perfectly acceptable provided that the original source is clearly indicated, which satisfies the attribution requirement. This can be done via the edit summary and by putting a note on the article talk page with a link to the original source. See Wikipedia:Translation and Category:Interwiki translation templates.

When copying material within Wikipedia, from one article to another, attribution is also required. For guidelines on copying and moving material within Wikipedia itself, see WP:MERGE, WP:SPLIT and WP:SUMMARY.

Attributing media copied from other sources

See also: Commons:Licensing

See also: 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 had 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 (although if the source is not free, duplicated creative text should be denoted in accordance with other policies). 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.

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 supect 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.

See also

• Wikipedia:Quotations (essay)
• Wikipedia:Close paraphrasing (essay)
• Wikipedia:Wikipedia Signpost/2009-04-13/Dispatches – Wikipedia Signpost article on plagiarism

Further reading

Articles, books, and journals

Template:Ref indent 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") Template:Ref indent-end

Digital academic resources

Template:Ref indent 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".) Template:Ref indent-end

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.