Wikipedia:Verifiability/temp

Verifiability is one of Wikipedia's four content policies. The other three are No original research, Neutral point of view and What Wikipedia is not. Jointly, these policies determine the type and quality of material that is acceptable in the main namespace. They should not be interpreted in isolation from one another, and editors should try to familiarize themselves with all four. The principles upon which these policies are based are negotiable only at the Foundation level.

Verifiability
The threshold for inclusion in Wikipedia is verifiability, not truth. "Verifiable" in this context means that any reader 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 material that is challenged or likely to be challenged, or it may be removed.

Burden of evidence

 * For how to write citations, see Citing sources

The burden of evidence lies with the editor who adds or restores material. Any material that is challenged or likely to be challenged needs a reliable source, which should be cited in the article. If an article topic has no reliable, third-party sources, Wikipedia should not have an article on it.

Any edit lacking a source may be removed, but editors may object if you remove material without giving them a chance to provide references. If you want to request a source for an unsourced statement, consider moving it to the talk page. Alternatively, you may tag the sentence by adding the template, or tag the article by adding  or. You can also make unsourced sentences invisible in the article by adding after it, until reliable sources have been provided. Leave a note on the talk page or edit summary explaining what you have done.

Be careful not to err too far on the side of not upsetting editors by leaving unsourced information in articles for too long, or at all in the case of information about living people. Jimmy Wales has said of this: "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."

Biographies of living persons
Biographical claims about living people need special care because of the effect they could have on someone's life, and because they could have legal consequences. Remove unsourced or poorly sourced contentious material about living persons immediately and do not move it to the talk page. This applies to the website as a whole, not only to the main namespace.

Reliable sources
The policy is that [a] reliable source for a claim is one that can withstand a reasonable level of scrutiny.

Articles should rely on reliable, third-party published sources with a reputation for fact-checking and accuracy. Sources should be appropriate to the claims made: exceptional claims require stronger sources.

A number of points to note:

•	The policy is principle-based. You need to apply common sense when interpreting it. •	The policy refers to source for a claim. This makes clear that a source can be reliable for some claims, but not others. •	reasonable level of scrutiny does not imply that a source needs to have impeccable reliability, just enough to be reasonably sure that it is reliable for the claim being made.

When considering whether a source is reliable, ask questions such as:

•	Who wrote the source? •	Why should the source know the fact it is being used to support? •	What is its reputation for reliability? •	Who has reviewed the source before publication? •	Should there be better sources for the same information, if so, can they be found? •	In particular, if the source is non-English, why can’t an English-language source more readily accessible to readers be found? •	Who published the source? •	Does another source contradict it? •	Do other sources confirm it (in which case consider citing some of the other sources too or instead)

In principle, there's no reason why we should not assess the reliability of self-published sources in the same way as we assess any other source. That they are self-published increases our scepticism about them, and we are more aware that they may be self-serving, which may render them unreliable. But being self-published, of itself, is not determinative of the source being unreliable.