^This principle was previously expressed on this policy page as "the threshold for inclusion is verifiability, not truth." See the essay, WP:Verifiability, not truth.
^A source "directly supports" a given piece of material if that information is directly present in the source, so that using this source to support this material is not a violation of Wikipedia:No original research. The location of any citation – including whether one is present in the article at all – is unrelated to whether a source directly supports the material. For questions about where and how to place citations, see WP:CITE, WP:CITELEAD, etc.
^Once an editor has provided any source that he or she believes, in good faith, to be sufficient, then any editor who later removes the material has an obligation to articulate specific problems that would justify its exclusion from Wikipedia (e.g., undue emphasis on a minor point, unencyclopedic content, etc.). All editors are then expected to help achieve consensus, and any problems with the text or sourcing should be fixed before the material is added back.
^It may be that the article contains so few citations that it is impractical to add specific citation needed tags, in which case consider tagging a section with . In the case of a disputed category or on a disambiguation page, consider asking for a citation on the talk page.
^When tagging or removing such material, please keep in mind that such edits can be easily misunderstood. Some editors object to others making chronic, frequent, and large-scale deletions of unsourced information, especially if unaccompanied by other efforts to improve the material. Do not concentrate only on material of a particular POV, as that may result in accusations that you are in violation of WP:NPOV. Also check to see whether the material is sourced to a citation elsewhere on the page. For all of these reasons, it is advisable to communicate clearly that you have a considered reason to believe that the material in question cannot be verified.
^"Zero information is preferred to misleading or false information", WikiEN-l, May 16, 2006: "I can NOT emphasize this enough. There seems to be a terrible bias among some editors that some sort of random speculative 'I heard it somewhere' pseudo information is to be tagged with a 'needs a cite' tag. Wrong. It should be removed, aggressively, unless it can be sourced. This is true of all information, but it is particularly true of negative information about living persons."
^This includes material such as documents in publicly accessible archives, inscriptions on monuments, gravestones, etc., that are available for anyone to see.
^ abSources that may have interests other than professional considerations in the matter being reported are considered to be conflicted sources. Further examples of sources with conflicts of interest include but are not limited to articles by any media group that promote the holding company of the media group or discredit its competitors; news reports by journalists having financial interests in the companies being reported or in their competitors; material (including but not limited to news reports, books, articles and other publications) involved in or struck down by litigation in any country, or released by parties involved in litigation against other involved parties, during, before or after the litigation; and promotional material released through media in the form of paid news reports. For definitions of sources with conflict of interest:
The Columbia Center for New Media Teaching and Learning, Columbia University mentions: "A conflict of interest involves the abuse – actual, apparent, or potential – of the trust that people have in professionals. The simplest working definition states: A conflict of interest is a situation in which financial or other personal considerations have the potential to compromise or bias professional judgment and objectivity. An apparent conflict of interest is one in which a reasonable person would think that the professional's judgment is likely to be compromised. A potential conflict of interest involves a situation that may develop into an actual conflict of interest. It is important to note that a conflict of interest exists whether or not decisions are affected by a personal interest; a conflict of interest implies only the potential for bias, not a likelihood. It is also important to note that a conflict of interest is not considered misconduct in research, since the definition for misconduct is currently limited to fabrication, falsification, and plagiarism."
The New York Times Company forwards this understanding: "Conflicts of interest, real or apparent, may come up in many areas. They may involve the relationships of staff members with readers, news sources, advocacy groups, advertisers, or competitors; with one another, or with the newspaper or its parent company. And at a time when two-career families are the norm, the civic and professional activities of spouses, family and companions can create conflicts or the appearance of conflicts."
^Self-published material is characterized by the lack of independent reviewers (those without a conflict of interest) validating the reliability of content. Further examples of self-published sources include press releases, material contained within company websites, advertising campaigns, material published in media by the owner(s)/publisher(s) of the media group, self-released music albums and electoral manifestos:
The University of California, Berkeley library states: "Most pages found in general search engines for the web are self-published or published by businesses small and large with motives to get you to buy something or believe a point of view. Even within university and library web sites, there can be many pages that the institution does not try to oversee."
Princeton University offers this understanding in its publication, Academic Integrity at Princeton (2011): "Unlike most books and journal articles, which undergo strict editorial review before publication, much of the information on the Web is self-published. To be sure, there are many websites in which you can have confidence: mainstream newspapers, refereed electronic journals, and university, library, and government collections of data. But for vast amounts of Web-based information, no impartial reviewers have evaluated the accuracy or fairness of such material before it's made instantly available across the globe."
^ abWhen there is dispute about whether a piece of text is fully supported by a given source, direct quotes and other relevant details from the source should be provided to other editors as a courtesy. Do not violate the source's copyright when doing so.
^An Enquiry concerning Human Understanding, Forgotten Books, 1984, pp. 82, 86; first published in 1748 as Philosophical enquiries concerning human Understanding, (or the Oxford 1894 edition 7067396M at para. 91) "A wise man ... proportions his belief to the evidence. ... That no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish; and even in that case there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force, which remains, after deducting the inferior." In the 18th century, Pierre-Simon Laplace reformulated the idea as "The weight of evidence for an extraordinary claim must be proportioned to its strangeness." Marcello Truzzi recast it again, in 1978, as "An extraordinary claim requires extraordinary proof." Carl Sagan, finally, popularized the concept broadly as "Extraordinary claims require extraordinary evidence" in 1980 on Cosmos: A Personal Voyage; this was the formulation originally used on Wikipedia.