Wikipedia:Verifiability
From Wikipedia, the free encyclopedia
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- To discuss the reliability of particular sources, see the reliable sources noticeboard.
| Wikipedia policy |
|---|
| Article standards |
| Neutral point of view Verifiability No original research Biographies of living persons |
| Working with others |
| Civility Consensus No personal attacks Dispute resolution No legal threats |
| Global principles |
| What Wikipedia is not Ignore all rules |
The threshold for inclusion in Wikipedia is verifiability, which means that readers should be able to check that material added to Wikipedia has already been published by a reliable source. Editors should provide a reliable source for quotations and for any material that is challenged or is likely to be challenged, or it may be removed.
Wikipedia:Verifiability is one of Wikipedia's core content policies. The others are Wikipedia:No original research and Wikipedia:Neutral point of view. Jointly, these policies determine the type and quality of material that is acceptable in Wikipedia articles. They should not be interpreted in isolation from one another, and editors should familiarize themselves with all three.
Contents |
[edit] Burden of evidence
- For how to write citations, see Wikipedia:Citing sources
The burden of evidence lies with the editor who adds or restores material. All quotations and any material challenged or likely to be challenged should be attributed to a reliable, published source using an inline citation.[1] The source should be cited clearly and precisely to enable readers to find the text that supports the article content in question.
If no reliable, third-party sources can be found for an article topic, Wikipedia should not have an article on it.
Any material lacking a reliable source may be removed, but editors may object if you remove material without giving them a chance to provide references. It is important to strike a balance between being quick to remove unsourced material that is clearly wrong or in some way damaging, and at the same time making sure that challenges are reasonable, and that editors are given a reasonable amount of time to find supporting sources. Before you challenge unsourced material, ask yourself whether you really do doubt that the material is accurate. Unsourced material should not be removed simply because of a difference of opinion.
The exception to this is that any unsourced material may be removed from biographical material about living persons at any time, and should be removed immediately if it is or even might be contentious.
If you want to request a source for an unsourced statement, consider moving it to the talk page. Alternatively, you may tag a sentence by adding the {{fact}} template, a section with {{unreferencedsection}}, or the article with {{refimprove}} or {{unreferenced}}. Use the edit summary to give an explanation of your edit. You may also leave a note on the talk page or an invisible HTML comment on the article page.[2]
[edit] Sources
[edit] Reliable sources
Articles should rely on reliable, third-party published sources with a reputation for fact-checking and accuracy.[3] Reliable sources are necessary both to substantiate material within articles and to give credit to authors and publishers in order to avoid plagiarism and copyright violations. Sources should directly support the information as it is presented in an article and should be appropriate to the claims made: exceptional claims require exceptional sources.
All articles must adhere to Wikipedia's neutrality policy, fairly representing all majority and significant-minority viewpoints that have been published by reliable sources, in rough proportion to the prominence of each view. Tiny-minority views and fringe theories need not be included, except in articles devoted to them.
In general, the most reliable sources are peer-reviewed journals and books published in university presses; university-level textbooks; magazines, journals, and books published by respected publishing houses; and mainstream newspapers. As a rule of thumb, the greater the degree of scrutiny involved in checking facts, analyzing legal issues, and scrutinizing the evidence and arguments of a particular work, the more reliable it is.
Academic and peer-reviewed publications are highly valued and usually the most reliable sources in areas where they are available, such as history, medicine and science. Material from reliable non-academic sources may also be used in these areas, particularly if they are respected mainstream publications. The appropriateness of any source always depends on the context. Where there is disagreement between sources, their views should be clearly attributed in the text.
For a guideline discussing the reliability of particular types of sources, see Wikipedia:Reliable sources (WP:RS). Because policies take precedence over guidelines, in the case of an inconsistency between this page and that one, this page has priority, and WP:RS should be updated accordingly. To discuss the reliability of specific sources, consult the Wikipedia:Reliable sources/Noticeboard.
[edit] Questionable sources
Questionable sources are those with a poor reputation for fact-checking. Such sources include websites and publications that express views that are widely acknowledged as extremist, are promotional in nature, or rely heavily on rumors and personal opinions. Questionable sources should only be used in articles about themselves. (See below.) Articles about such sources should not repeat any contentious claims the source has made about third parties, unless those claims have also been published by reliable sources.
[edit] Self-published sources (online and paper)
Anyone can create a website or pay to have a book published, then claim to be an expert in a certain field. For that reason, self-published books, newsletters, personal websites, open wikis, blogs, forum postings, and similar sources are largely not acceptable.[4]
Self-published material may, in some circumstances, be acceptable 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. However, caution should be exercised when using such sources: if the information in question is really worth reporting, someone else is likely to have done so.
Self-published sources should never be used as third-party sources about living persons, even if the author is a well-known professional researcher or writer; see WP:BLP#Reliable sources.
Articles and posts on Wikipedia may not be used as sources.
[edit] Self-published and questionable sources in articles about themselves
Self-published and questionable sources may be used as sources in articles about themselves, so long as:
- the material used is relevant to their notability;
- it is not contentious;
- it is not unduly self-serving;
- it does not involve claims about third parties;
- it does not involve claims about events not directly related to the subject;
- there is no reasonable doubt as to who authored it;
- the article is not based primarily on such sources.
[edit] Non-English sources
Because this is the English Wikipedia, for the convenience of our readers, editors should use English-language sources in preference to sources in other languages, assuming the availability of an English-language source of equal quality, so that readers can easily verify that the source material has been used correctly. Where editors use non-English sources, they should ensure that readers can verify for themselves the content of the original material and the reliability of its author/publisher.
Where editors use a non-English source to support material that others might challenge, or translate any direct quote, they need to quote the relevant portion of the original text in a footnote or in the article, so readers can check that it agrees with the article content. Translations published by reliable sources are preferred over translations made by Wikipedia editors.
[edit] Exceptional claims require exceptional sources
- See also: Wikipedia:Fringe theories
Certain red flags should prompt editors to examine the sources for a given claim:
- surprising or apparently important claims not covered by mainstream sources;
- reports of a statement by someone that seems out of character, embarrassing, controversial, or against an interest they had previously defended;
- claims that are contradicted by the prevailing view within the relevant community, or which would significantly alter mainstream assumptions, especially in science, medicine, history, politics, and BLPs. Be particularly careful when proponents of such claims say there is a conspiracy to silence them.
Exceptional claims in Wikipedia require high-quality reliable sources; if such sources are not available, the material should not be included. Also be sure to adhere to other policies, such as the policy for biographies of living persons and the undue weight provision of WP:NPOV.
[edit] See also
- Wikipedia:Template messages/Sources of articles
- WikiProject Fact and Reference Check
- Forum for Encyclopedic Standards
- WikiProject Resource Exchange
- Wikipedia:Free online resources
- Wikipedia:NPOV, V and OR
[edit] Notes and references
- ^ When content in Wikipedia requires direct substantiation, the established convention is to provide an inline citation to the supporting references. The rationale is that this provides the most direct means to verify whether the content is consistent with the references. Alternative conventions exist, and are acceptable when they provide clear and precise attribution for the article's assertions, but inline citations are considered "best practice" under this rationale. For more details, please consult Wikipedia:Citing_sources#How_to_cite_sources.
- ^ See Help:Editing#Basic text formatting: "Invisible comments to editors only appear while editing the page. If you wish to make comments to the public, you should usually go on the talk page."
- ^ The word "source", as used in Wikipedia, has three related meanings: the piece of work itself, the creator of the work, and the publisher of the work. All three affect reliability.
- ^ "Blogs" in this context refers to personal and group blogs. Some newspapers host interactive columns that they call blogs, and these may be acceptable as sources so long as the writers are professionals and the blog is subject to the newspaper's full editorial control. Where a news organization publishes the opinions of a professional but claims no responsibility for the opinions, the writer of the cited piece should be attributed (e.g. "Jane Smith has suggested..."). Posts left by readers may never be used as sources.
[edit] Further reading
- Jimmy Wales. "WikiEN-l insist on sources", WikiEN-l mailing list, July 19, 2006.
