Wikipedia:Reliable sources

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This page documents an English Wikipedia content guideline. It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense and the occasional exception. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page.
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This page in a nutshell: Articles should be based on reliable, third-party, published sources with a reputation for fact-checking and accuracy.
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This is a guideline discussing the reliability of particular types of sources. The relevant policies on sources are Wikipedia:Verifiability and Wikipedia:No original research, and additional restrictions in biographies of living people. Wikipedia articles should cover all major and significant-minority views that have been published by reliable sources. See Wikipedia:Neutral point of view.

Wikipedia articles[1] should rely primarily on reliable, third-party, published sources (although reliable self-published sources are allowable in some situations - see below). Reliable sources are credible published materials with a reliable publication process; their authors are generally regarded as trustworthy or authoritative in relation to the subject at hand. How reliable a source is depends on context. As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication. Sources should directly support the information as it is presented in an article and should be appropriate to the claims made; if an article topic has no reliable sources, Wikipedia should not have an article on it. See Wikipedia:Reliable sources/Noticeboard for queries about the reliability of particular sources.

Contents

Overview

Articles should rely on reliable, third-party, published sources with a reputation for fact-checking and accuracy. This means that we only publish the opinions of reliable authors, and not the opinions of Wikipedians who have read and interpreted primary source material for themselves. The following specific examples cover only some of the possible types of reliable sources and source reliability issues, and are not intended to be exhaustive. Proper sourcing always depends on context; common sense and editorial judgment are an indispensable part of the process.

The term "published" is most commonly associated with text materials. However, audio, video, and multimedia materials that have been recorded then broadcast, distributed, or archived by a reputable third-party may also meet the necessary criteria to be considered reliable source. Like text sources, media sources must be produced by a reliable third-party and be properly cited. Additionally, an archived copy of the media must exist. It is useful but by no means necessary for the archived copy to be accessible via the internet.

Scholarship

Further information: Wikipedia:Verifiability#Reliable sources

Many Wikipedia articles rely on scholarly material. Academic and peer-reviewed publications are usually the most reliable sources when available. However, some scholarly material may be outdated, superseded by more recent research, in competition with alternate theories, or controversial within the relevant field. Reliable non-academic sources may also be used, particularly material from reputable mainstream publications. Wikipedia articles should cover all significant views, doing so in proportion to their published prominence among the most reliable sources. The choice of appropriate sources depends on context and information should be clearly attributed where there are conflicting sources.

  • Material that has been vetted by the scholarly community is regarded as reliable; this means published in reputable peer-reviewed sources or by well-regarded academic presses.
  • Items that are signed are preferable to unsigned articles.
  • The scholarly acceptance of a source can be verified by confirming that the source has entered mainstream academic discourse, for example by checking the number of scholarly citations it has received in citation indexes. A corollary is that journals not included in such indexes should be used with caution.
  • Isolated studies are usually considered tentative and may change in the light of further academic research. The reliability of a single study depends on the field. Studies relating to complex and abstruse fields, such as medicine, are less definitive. Avoid undue weight when using single studies in such fields. Meta-analyses, textbooks, and scholarly review articles are preferred to provide proper context, where available.

News organizations

Further information: Wikipedia:Verifiability, Wikipedia:Biographies of living persons, and Wikipedia:Reliable sources (medicine-related articles)

Material from mainstream news organizations is welcomed, particularly the high-quality end of the market, such as The Washington Post, The Times in Britain, and The Associated Press. Some caveats:

  • News reporting is distinct from opinion pieces. Opinion pieces are only reliable for statements as to the opinion of their authors, not for statements of fact, and should be attributed in-text. In articles about living persons, only material from high-quality news organizations should be used.
  • While the reporting of rumors has a news value, Wikipedia is an encyclopedia and should only include information verified by reliable sources. Wikipedia is not the place for passing along gossip and rumors.
  • For information about academic topics, such as physics or ancient history, scholarly sources are preferred over news stories. Newspapers tend to misrepresent results, leaving out crucial details and reporting discoveries out of context. For example, news reports often fail to adequately report methodology, errors, risks, and costs associated with a new scientific result or medical treatment.
  • Some news organizations have used Wikipedia articles as the sole source for their work.[2] To avoid this indirect self-referencing, editors should ensure that material from news organizations is not the only existing source outside of Wikipedia. Generally, sources that predate the material's inclusion in Wikipedia are preferable.

Self-published sources

Main article: Wikipedia:Verifiability#Self-published sources (online and paper)

Self-published sources are largely not acceptable, though may be used only in limited circumstances, with caution, when produced by an established expert on the topic of the article whose work in the relevant field has previously been published by reliable third-party publications.

Extremist and fringe sources

Further information: Wikipedia:Verifiability#Questionable sources, Wikipedia:Fringe theories, and Wikipedia:PSCI

Organizations and individuals that express views that are widely acknowledged by reliable sources as fringe, pseudo-academic,[3] or extremist may be used as sources of information about those organisations or individuals, especially in articles about those organisations or individuals, without the requirement that they be published experts in the field, so long as:

  1. it is not unduly self-serving;
  2. it does not involve claims about third parties;
  3. it does not involve claims about events not directly related to the subject;
  4. there is no reason to doubt its authenticity;
  5. the article is not based primarily on such sources;

An individual extremist or fringe source may be entirely excluded if there is no independent evidence that it is prominent enough for mention. Fringe and extremist sources must not be used to obscure or describe the mainstream view, nor used to indicate a fringe theory's level of acceptance.

Reliability in specific contexts

Biographies of living persons

Main article: Wikipedia:Biographies of living persons#Sources

Editors must take particular care when writing biographical material about living persons, for legal reasons and in order to be fair. Remove unsourced or poorly sourced contentious material immediately if it is about a living person, and do not move it to the talk page. This applies to any material related to living persons on any page in any namespace, not just article space.

Primary, secondary, and tertiary sources

Main article: Wikipedia:No original research#Primary, secondary and tertiary sources

Wikipedia articles should be based on reliable secondary sources. This means that while primary or tertiary sources can be used to support specific statements, the bulk of the article should rely on secondary sources.

Tertiary sources such as compendia, encyclopedias, textbooks, and other summarizing sources may be used to give overviews or summaries, but should not be used in place of secondary sources for detailed discussion. Wikipedia itself, although a tertiary source, should not be used as a source within articles.

Primary sources, on the other hand, are often difficult to use appropriately. While they can be reliable in many situations, they must be used with caution in order to avoid original research.

Consensus

The existence of a consensus within an academic community may be indicated, for example, by independent secondary or tertiary sources that come to the same conclusion. The statement that all or most scientists, scholars, or ministers hold a certain view requires a reliable source. Without it, opinions should be identified as those of particular, named sources. Editors should avoid original research especially with regard to making blanket statements based on novel syntheses of disparate material.

Usage by other sources

How accepted, high-quality reliable sources use a given source provides evidence, positive or negative, for its reliability and reputation. The more widespread and consistent this use is, the stronger the evidence. For example, widespread citation without comment for facts is evidence of a source's reputation and reliability for similar facts, while widespread doubts about reliability weigh against it. If outside citation is the main indicator of reliability, particular care should be taken to adhere to other guidelines and policies, and to not represent unduly contentious or minority claims. The goal is to reflect established views of sources as far as we can determine them.

Statements of opinion

Some sources may be considered reliable for statements as to their author's opinion, but not for statements of fact. A prime example of this are Op-ed columns that are published in mainstream newspapers. When discussing what is said in such sources, it is important to directly attribute the material to its author, and to do so in the main text of the Wikipedia article so readers know that we are discussing someone's opinion.

There is, however, an important exception to sourcing statements of opinion: Never use self-published books, zines, websites, webforums, blogs and tweets as a source for material about a living person, unless written or published by the subject of the biographical material. "Self-published blogs" in this context refers to personal and group blogs (see: WP:BLP#Sources and WP:BLP#Using the subject as a self-published source).

Note that otherwise reliable news sources--for example, the website of a major news organization--that happens to publish in a "blog" style format for some or all of its content may be considered to be equally reliable as if it were published in a more "traditional" 20th-century format of a classic news story. However, the distinction between "opinion pieces" and news should be considered carefully.

Other examples

See Wikipedia:Reliable source examples for examples of the use of statistical data, advice by subject area (including history, physical sciences, mathematics and medicine, law, business and commerce, popular culture and fiction), and the use of electronic or online sources.

Notes

  1. ^ Articles include anything in the main namespace. Most other pages, such as Wikipedia's policies and guidelines, are exempt from this requirement.
  2. ^ A variety of these incidents have been documented by Private Eye and others and discussed on Wikipedia, where incorrect details from articles added as vandalism or otherwise have appeared in newspapers
  3. ^ Examples of such views include certain forms of revisionist history and pseudoscience

See also

External links

Retrieved from "http://en.wikipedia.org/wiki/Wikipedia:Reliable_sources"
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