Wikipedia:Plagiarism

Plagiarism is the incorporation of someone else's work without providing adequate credit. This guideline addresses where 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.

By Wikipedia's verifiability policy, articles should be based on previously published sources. These must be handled appropriately to avoid plagiarism.

If the external work is under standard copyright, then duplicating its text with little, or no, alteration into a Wikipedia article is usually a copyright violation, unless duplication is limited and clearly indicated in the article by quotation marks, or some other acceptable method (such as block quotations).

If the external work is under a copyleft license that is compatible with Creative Commons Attribution/Share-Alike License 3.0, it may be acceptable to include the text directly into a Wikipedia article if it otherwise meets policies and guidelines and if adequate attribution is provided. Most copyleft licences require that attribution be given; omitting such attribution is not only plagiarism, but also a copyright violation. Text from works with incompatible licensing must be treated as if the text were under the standard copyright notice.

Works that are in the public domain because they were never protected, or their copyright has lapsed, carry no legal requirement for attribution, but most articles in Wikipedia that are derived from such external works attribute the text to the public domain source.

Attribution for compatibly licensed and public domain text is generally provided through the use of an appropriate attribution template, or similar annotation, 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:
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.

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 in your own words, and citing your source;
• direct speech: marking material you copy as a verbatim quote, using quotation marks, and citing your source; for example:

• John said: "Cottage Cheese for Beginners is the most boring book I've ever read."

• indirect speech: using in-text attribution without quotation marks, and citing your source; for example:

• John said Cottage Cheese for Beginners was the most boring book he had ever read.

• properly attributing any public-domain, or free-content text, that you add to 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 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 Wikipedia'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 been 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. 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. 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. 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 Wikipedia's policy on verifiability.
• Simple logical deductions. Complex logical deductions, in contrast, generally require a citation, because of Wikipedia'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 extensively copied into Wikipedia articles. Limited amounts of text can be copied from such works providing they satisfy the Wikipedia copyright policy 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 it 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 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.
• 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 be cited, as not 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 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 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 adequate attribution is provided, but it depends on the specific license. Most copyleft licenses require that author 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 licensing incompatibility between the licence of some copyleft sources and the Wikipedia content license—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 Wikipedia articles. 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 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

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).

Re-use of copyright expired text is 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

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.

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 within the edit summary is required. For guidelines on copying and moving material within English Wikipedia itself, see WP:MERGE, WP:SPLIT and WP:SUMMARY.

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 Cite}}. 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.
• Some Probable Instances of Plagiarism in the Work of an Academic