Wikipedia:Reliable sources | reliability in specific contexts

Reliability in specific contexts

Biographies of living persons

Editors must take particular care when writing biographical material about living persons. Contentious material about a living person that is unsourced or poorly sourced should be removed immediately; 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

Wikipedia articles should be based mainly on reliable secondary sources, i.e., a document or recording that relates or discusses information originally presented elsewhere.

Reputable tertiary sources, such as introductory-level university textbooks, almanacs, and encyclopedias, may be cited. However, although Wikipedia articles are tertiary sources, Wikipedia employs no systematic mechanism for fact checking or accuracy. Thus, Wikipedia articles (and Wikipedia mirrors) in themselves are not reliable sources for any purpose (except as sources on themselves per WP:SELFSOURCE). Because Wikipedia forbids original research, there is nothing reliable in it that is not citable with something else.

Primary sources are often difficult to use appropriately. Although they can be both reliable and useful in certain situations, they must be used with caution in order to avoid original research. Although specific facts may be taken from primary sources, secondary sources that present the same material are preferred. Large blocks of material based purely on primary sources should be avoided. All interpretive claims, analyses, or synthetic claims about primary sources must be referenced to a secondary source, rather than original analysis of the primary-source material by Wikipedia editors.

When editing articles in which the use of primary sources is a concern, in-line templates, such as {{primary source-inline}} and {{better source}}, or article templates, such as {{primary sources}} and {{refimprove science}}, may be used to mark areas of concern.

Medical claims

Ideal sources for biomedical assertions include general or systematic reviews in reliable, third-party, published sources, such as reputable medical journals, widely recognised standard textbooks written by experts in a field, or medical guidelines and position statements from nationally or internationally reputable expert bodies. It is vital that the biomedical information in all types of articles be based on reliable, third-party, published sources and accurately reflect current medical knowledge.


The accuracy of quoted material is paramount and the accuracy of quotations from living persons is especially sensitive. To ensure accuracy, the text of quoted material is best taken from (and cited to) the original source being quoted. If this is not possible, then the text may be taken from a reliable secondary source (ideally one that includes a citation to the original). No matter where you take the quoted text from, it is important to make clear the actual source of the text, as it appears in the article.

Partisan secondary sources should be viewed with suspicion as they may misquote or quote out of context. In such cases, look for neutral corroboration from another source.

Any analysis or interpretation of the quoted material, however, should rely on a secondary source (see Wikipedia:No original research).

Academic consensus

A statement that all or most scientists or scholars hold a certain view requires reliable sourcing that directly says that all or most scientists or scholars hold that view. Otherwise, individual 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. Stated simply, any statement in Wikipedia that academic consensus exists on a topic must be sourced rather than being based on the opinion or assessment of editors. Review articles, especially those printed in academic review journals that survey the literature, can help clarify academic consensus.

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, whereas 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 asserted as fact. For example, an inline qualifier might say "[Author XYZ] says....". A prime example of this is opinion pieces in sources recognized as reliable. When using them, it is best to clearly attribute the opinions in the text to the author and make it clear to the reader that they are reading an opinion.

Otherwise reliable news sources—for example, the website of a major news organization—that publish in a blog-style format for some or all of their content may be as reliable as if published in standard news article format.

There is an important exception to sourcing statements of fact or 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 Wikipedia:Biographies of living persons § Reliable sources and Wikipedia:Biographies of living persons § Using the subject as a self-published source.

Breaking news

Breaking-news reports often contain serious inaccuracies. As an electronic publication, Wikipedia can and should be up to date, but Wikipedia is not a newspaper and it does not need to go into all details of a current event in real time. It is better to wait a day or two after an event before adding details to the encyclopedia, than to help spread potentially false rumors. This gives journalists time to collect more information and verify claims, and for investigative authorities to make official announcements. The On the Media Breaking News Consumer's Handbook[17] contains several suggestions to avoid spreading unreliable and false information, such as distrusting anonymous sources and unconfirmed reports, as well as reports attributed to other news media; seeking multiple sources; seeking eyewitness reports; being wary of potential hoaxes, and being skeptical of reports of possible additional attackers in mass shootings.

Claims sourced to initial news reports should be immediately replaced with better-researched ones as soon as they are published, especially if those original reports contained inaccuracies. All breaking-news stories, without exception, are primary sources, and must be treated with caution: see Wikipedia:No original research § Primary, secondary and tertiary sources.

When editing a current-event article, keep in mind recentism bias.

The {{current}}, {{recent death}}, or another current-event-related template can be added to the top of articles about a breaking-news event to alert readers to the fact that some information in the article may be inaccurate, and to draw attention to the need to add improved sources as they become available. These templates should not be used, however, to mark articles on subjects or persons in the news; if they were, hundreds of thousands of articles would have such a template, but to no significant advantage (see also Wikipedia:No disclaimers in articles).