Verifiability

Verifiability on Wikipedia is the adeptness to adduce reliable sources that anon abutment the advice in an article. All advice in Wikipedia accept to be verifiable, but because added behavior and guidelines aswell access content, verifiability does not agreement inclusion. The beginning for admittance in Wikipedia is verifiability, not truth—whether readers can analysis that actual in Wikipedia has already been appear by a reliable source, not whether editors anticipate it is true. under discussion

It accept to be accessible to aspect all advice in Wikipedia to reliable, appear sources that are adapted for the agreeable in question. However, in convenance it is alone all-important to accommodate inline citations for quotations and for any advice that has been challenged or that is acceptable to be challenged.1 Adapted citations agreement that the advice is not aboriginal research, and acquiesce readers and editors to analysis the antecedent actual for themselves. Any actual that requires a commendation but does not accept one may be removed. Unsourced advancing actual about active humans accept to be removed immediately. For advice on abacus citations, see Citing sources. This action applies to all actual in the mainspace.

Verifiability, No aboriginal analysis and Neutral point of appearance are Wikipedia's amount agreeable policies. They plan calm to actuate content, so editors should accept the key credibility of all three. Articles accept to aswell accede with the absorb policy.

When a reliable source is required

Anything challenged or acceptable to be challenged

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All quotations and any actual challenged or acceptable to be challenged have to be attributed to a reliable appear antecedent application an inline citation. The commendation should absolutely analyze the source, and the area aural the antecedent (specifying page, section, or such capacity as may be appropriate) area the actual is to be found. See Citing sources for data of how to do this.

Burden of evidence

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The accountability of affirmation lies with the editor who adds or restores material. You may abolish any actual defective an inline commendation to a reliable source. Whether and how bound abatement should appear depends on the actual and the all-embracing accompaniment of the article; accede abacus a commendation bare tag as an acting step.2 Editors ability commodity if you abolish actual after giving them time to accommodate references. It has consistently been acceptable convenance to try to acquisition and adduce acknowledging sources yourself. Do not leave unsourced or ailing sourced actual in an commodity if it ability accident the acceptability of active people; you should aswell be acquainted of how the BLP action applies to groups.3

Reliable sources

What counts as a reliable source

The chat "source" in Wikipedia has three meanings: the plan itself (a document, article, paper, or book), the architect of the plan (for example, the writer), and the administrator of the plan (for example, Oxford University Press). All three can affect reliability.

Articles should be based on reliable, third-party, appear sources with a acceptability for fact-checking and accuracy. Antecedent actual accept to accept been appear (made accessible to the accessible in some form); abstruse abstracts are not advised reliable. Sources should anon abutment the actual presented in an commodity and should be adapted to the claims made. The account of any antecedent depends on the context. In general, the best sources accept a able anatomy in abode for blockage or allegory facts, acknowledged issues, evidence, and arguments; as a aphorism of thumb, the greater the bulk of analysis accustomed to these issues, the added reliable the source. Agreeable accompanying to active humans or anesthetic should be sourced abnormally carefully.

Where available, bookish and peer-reviewed publications are usually the a lot of reliable sources, such as in history, medicine, and science. But they are not the alone reliable sources in such areas. Actual from reliable non-academic sources may aswell be used, decidedly if it appears in admired boilerplate publications. Added reliable sources cover university-level textbooks, books appear by admired publishing houses, magazines, journals, and boilerplate newspapers. Electronic media may aswell be used, accountable to the aforementioned criteria. See data in Wikipedia:Identifying reliable sources and Wikipedia:Search engine test.

Newspaper and annual blogs

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Several newspapers, magazines, and added account organizations host columns on their web sites that they alarm blogs. These may be adequate as sources if the writers are professionals but should be acclimated with attention because the blog may not be accountable to the account organization's accustomed actuality blockage process.4 Where a account alignment publishes an assessment section in a blog, aspect the account to the biographer (e.g. "Jane Smith wrote..."). Never use blog posts that are larboard by readers as sources. For blogs that are not reliable sources, see Self-published sources below.

Reliable sources noticeboard and WP:IRS

Further information: Wikipedia:Reliable sources noticeboard and Wikipedia:Identifying reliable sources

To altercate the believability of a specific antecedent for a accurate statement, argue the reliable sources noticeboard, which seeks to administer this action to accurate cases. For a guideline discussing the believability of accurate types of sources, see Wikipedia:Identifying reliable sources (WP:IRS). In the case of aberration amid this action and the WP:IRS guideline, or any added guideline accompanying to sourcing, this action has priority.

Sources that are usually not reliable

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Questionable sources

Questionable sources are those with a poor acceptability for blockage the facts, or which abridgement allusive beat oversight, or those with an credible battle of interest.5 Such sources include, but are not bound to, websites and publications cogent angle that are broadly advised by added sources to be agitator or promotional, or which await heavily on rumor and claimed opinion. Ambiguous sources should be acclimated alone as sources of actual on themselves, abnormally in online writing about themselves; see below. They are clashing for citation advancing claims about third parties.

Self-published sources

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Further information: Wikipedia:Biographies of active persons#Avoid self-published sources

Anyone can actualize a claimed web page or pay to accept a book published, again affirmation to be an able in a assertive field. For that reason, self-published media, such as books, patents, newsletters, claimed websites, accessible wikis, claimed or accumulation blogs, Internet appointment postings, and tweets, are abundantly not adequate as sources. Self-published able sources may be advised reliable if produced by an accustomed able on the affair of the commodity whose plan in the accordant acreage has ahead been appear by reliable third-party publications.4 Take affliction if application such sources: if the advice in catechism is absolutely account reporting, anyone abroad will apparently accept done so.6 Never use self-published sources as third-party sources about active people, even if the columnist is an expert, acclaimed able researcher, or writer.

Self-published or ambiguous sources as sources on themselves

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Self-published and ambiguous sources may be acclimated as sources of advice about themselves, usually in online writing about themselves or their activities, after the claim in the case of self-published sources that they be appear experts in the field, so continued as:

the actual is not disproportionately self-serving;

it does not absorb claims about third parties;

it does not absorb claims about contest not anon accompanying to the source;

there is no reasonable agnosticism as to its authenticity;

the commodity is not based primarily on such sources.

This action aswell applies to pages on amusing networking sites such as Twitter, Tumblr, and Facebook.

Wikipedia and sources that mirror or use it

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Do not use online writing from Wikipedia or from websites that mirror its agreeable as sources, because this would bulk to self-reference. Similarly, do not use sources that present actual basic from Wikipedia to abutment that aforementioned actual in Wikipedia, as this would actualize annular sourcing. Citation Wikipedia to abutment a anecdotic account about Wikipedia itself is not a anatomy of annular referencing. Instead it is the use of Wikipedia as a primary antecedent and should chase the accordant action for the use of primary sources

Accessibility

Access to sources

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See also: Wikipedia:WikiProject Resource Exchange, Wikipedia:Offline sources, and Wikipedia:Reliable sources/Cost

Verifiability in this ambience agency that added humans should be able to analysis that actual in a Wikipedia commodity has been appear by a reliable source. The assumption of verifiability implies annihilation about affluence of admission to sources: some online sources may crave payment, while some book sources may be accessible alone in university libraries. WikiProject Resource Exchange may be able to abetment in accepting antecedent material.

Non-English sources

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See also: Wikipedia:Translators available

Because this is the English Wikipedia, English-language sources are adopted over non-English ones, bold English sources of according superior and appliance are available.

When commendation a antecedent in a altered language, accommodate the aboriginal argument and an English translation, either in the physique of the commodity or in a footnote.

When citation a non-English antecedent for information, it is not consistently all-important to accommodate a translation. However, if a catechism should appear as to whether the non-English aboriginal in fact supports the information, accordant portions of the aboriginal and a adaptation should be accustomed in a footnote, as a courtesy.7

Translations appear by reliable sources are adopted over translations by Wikipedians, but translations by Wikipedians are adopted over apparatus translations. When application a apparatus adaptation of antecedent material, editors should be analytic assertive that the adaptation is authentic and the antecedent is appropriate. When announcement aboriginal antecedent material, be accurate not to breach copyright; see the fair-use guideline.

Other issues

Tagging a sentence, section, or article

Further information: Wikipedia:Template messages/Sources of articles

If you wish to appeal a antecedent for an unsourced statement, accede tagging a book with the {{citation needed}} arrangement by autograph {{cn}} or {{fact}}. Added templates are accessible actuality for tagging sections or absolute articles. Alternatively, leave a agenda on the allocution page requesting a source, or move the actual to the allocution page and ask for a antecedent there. To appeal analysis that a advertence supports the text, tag it with {{verification needed}}. Actual that fails analysis may be tagged with {{failed verification}} or removed. If application templates to tag material, it is accessible to added editors if you explain your account in the template, adapt summary, or on the allocution page.

Special affliction should be acclimated in attention to actual about active people. Unsourced or ailing sourced advancing actual about active humans should be removed immediately, not tagged or confused to the allocution page.

Exceptional claims crave aberrant sources

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See also: Wikipedia:Fringe theories

Any aberrant affirmation requires assorted high-quality sources.8 Red flags that should alert added attention include:

hasty or allegedly important claims not covered by assorted boilerplate sources;

challenged claims that are accurate absolutely by primary or self-published sources or those with an credible battle of interest;5

letters of a account by anyone that seems out of character, or adjoin an absorption they had ahead defended;

claims that are contradicted by the prevailing appearance aural the accordant community, or that would decidedly adapt boilerplate assumptions, abnormally in science, medicine, history, politics, and biographies of active people. This is abnormally accurate if proponents say there is a cabal to blackout them.

Verifiability and other principles

Copyright and plagiarism

Further information: Wikipedia:Copyright, Wikipedia:Plagiarism, Wikipedia:MOS#Attribution, and Wikipedia:CITE#In-text attribution

Take affliction to abstain appropriation and breaches of absorb if application sources. Summarize antecedent actual in your own words as abundant as possible; if commendation or carefully apery a antecedent use an inline citation, and in-text allegation area appropriate.

Material that violates the copyrights of others per contributors' rights and obligations should not be cited. Bond to websites that affectation copyrighted works is adequate as continued as the website has accountant the work, or uses the plan in a way adjustable with fair use. Knowingly administering others to actual that violates absorb may be advised accessory absorb infringement. If there is acumen to accept that a antecedent is in abuse of copyright, do not adduce it. This is decidedly accordant if bond to sites such as YouTube, area due affliction should be taken to abstain bond to actual that violates copyright.

Neutrality

Further information: Wikipedia:Neutral point of view

All online writing accept to attach to the Aloof point of appearance action (NPOV), adequately apery all majority and significant-minority viewpoints appear by reliable sources, in asperous admeasurement to the bulge of anniversary view. Tiny-minority angle charge not be included, except in online writing adherent to them. Area there is altercation amid sources, use in-text attribution: "John Smith argues that X, while Paul Jones maintains that Y," followed by an inline citation. Sources themselves do not charge to beforehand a aloof point of view; absolutely abounding reliable sources are not neutral. Our job as editors is artlessly to present what the reliable sources say.

Notability

Further information: Wikipedia:Notability

If no reliable third-party sources can be begin on a topic, Wikipedia should not accept an commodity on it.

Original research

Further information: Wikipedia:No aboriginal research

The "No aboriginal research" action (NOR) is carefully accompanying to the Verifiability policy. Among its requirements are:

All actual in Wikipedia online writing accept to be attributable to a reliable appear source. This agency that a antecedent accept to abide for it, whether or not it is cited in the article.

Sources accept to abutment the actual acutely and directly: cartoon inferences from assorted sources to beforehand a atypical position is banned by the NOR policy.7

Base online writing abundantly on reliable accessory sources. While primary sources are adapted in some cases, relying on them can be problematic. For added information, see the Primary, secondary, and tertiary sources area of the NOR policy, and the Misuse of primary sources area of the BLP policy.