Wikipedia:Surgenti affidabbili

This is a guideline discussing the reliability of particular types of sources. The relevant policies on sources are Wikipedia:Verifiability and Wikipedia:No original research, and additional restrictions in biographies of living people. Wikipedia articles should cover all major and significant-minority views that have been published by reliable sources. See Wikipedia:Neutral point of view.

Wikipedia articles should use reliable, third-party, published sources. Reliable sources are credible published materials with a reliable publication process; their authors are generally regarded as trustworthy or authoritative in relation to the subject at hand. How reliable a source is depends on context. As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication. Sources should directly support the information as it is presented in an article and should be appropriate to the claims made; if an article topic has no reliable sources, Wikipedia should not have an article on it. See Wikipedia:Reliable sources/Noticeboard for queries about the reliability of particular sources.

Overview

Articles should rely on reliable, third-party, published sources with a reputation for fact-checking and accuracy. This means that we only publish the opinions of reliable authors, and not the opinions of Wikipedians who have read and interpreted primary source material for themselves. The following specific examples cover only some of the possible types of reliable sources and source reliability issues, and are not intended to be exhaustive. Proper sourcing always depends on context; common sense and editorial judgment are an indispensable part of the process.

Scholarship

Template:See Many Wikipedia articles rely on scholarly material. Academic and peer-reviewed publications are usually the most reliable sources when available. However, some scholarly material may be outdated, superseded by more recent research, in competition with alternate theories, or controversial within the relevant field. Reliable non-academic sources may also be used, particularly material from reputable mainstream publications. Wikipedia articles should cover all significant views, doing so in proportion to their published prominence among the most reliable sources. The choice of appropriate sources depends on context and information should be clearly attributed where there are conflicting sources.

Material that has been vetted by the scholarly community is regarded as reliable; this means published in reputable peer-reviewed sources and/or by well-regarded academic presses.
Items that are signed are preferable to unsigned articles.
The scholarly acceptance of a source can be verified by confirming that the source has entered mainstream academic discourse, for example by checking the number of scholarly citations it has received in citation indexes.
Isolated studies are usually considered tentative and may change in the light of further academic research. The reliability of a single study depends on the field. Studies relating to complex and abstruse fields, such as medicine, are less definitive. Avoid undue weight when using single studies in such fields. Meta-analyses, textbooks, and scholarly review articles are preferred to provide proper context, where available.

News organizations

Template:See Material from mainstream news organizations is welcomed, particularly the high-quality end of the market, such as The Washington Post, The Times in Britain, and The Associated Press. Some caveats:

News reporting is distinct from opinion pieces. Opinion pieces are only reliable for statements as to the opinion of their authors, not for statements of fact, and should be attributed in-text. In articles about living persons, only material from high-quality news organizations should be used.

While the reporting of rumors has a news value, Wikipedia is an encyclopedia and should only include information verified by reliable sources. Wikipedia is not the place for passing along gossip and rumors.

For information about academic topics, such as physics or ancient history, scholarly sources are preferred over news stories. Newspapers tend to misrepresent results, leaving out crucial details and reporting discoveries out of context. For example, news reports often fail to adequately report methodology, errors, risks, and costs associated with a new scientific result or medical treatment.

Self-published sources

Template:Main Self-published sources may be used only in very limited circumstances; see above. When removing or challenging a reference to a self-published source, it is best to explain how it is being used inappropriately, rather than simply point out that the source is self-published.

Extremist and fringe sources

Template:Main Template:See Organizations and individuals that express views that are widely acknowledged by reliable sources as extremist should be used only as sources about themselves and in articles about themselves or their activities, or where they are necessary to explain other groups or events; any information used must be directly relevant to the subject. The material taken from such sources should not be contentious, and it should not involve claims made about third parties, unless those claims have also been published by reliable sources. Articles should not be based primarily on such sources.

Organizations and individuals that promote what are widely agreed to be fringe theories (that is, views held by a small minority, in direct contrast with the mainstream view in their field), such as certain forms of revisionist history or pseudoscience, should only be used as sources about themselves or, if correctly attributed as being such, to detail the views of the proponents of that subject. Use of these sources must not obfuscate the description of the mainstream view, nor should these fringe sources be used to describe the mainstream view or the level of acceptance of the fringe theory. When using such sources, reliable mainstream sources must be found in order to allow the dispute to be characterized fairly, presenting the mainstream view as the mainstream, and the fringe theory as a minority fringe view.

Certain extremist and fringe sources may be entirely excluded from Wikipedia if there is no independent acknowledgment that the sources in question are representative of an opinion prominent enough for inclusion.

Reliability in specific contexts

Biographies of living persons

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Editors must take particular care when writing biographical material about living persons, for legal reasons and in order to be fair. Remove unsourced or poorly sourced contentious material immediately if it is about a living person, and 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

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Primary sources — writings on or about a topic by key figures of the topic — may be allowable, but should be restricted to purely descriptive explanations of the subject or its core concepts. They should not be used for interpretation or evaluation; use the interpretations and evaluations of reliable secondary sources for that purpose. Tertiary sources — compendiums, encyclopedias, textbooks, and other summarizing sources — may be used to give overviews or summaries, but should not be used in place of secondary sources for detailed discussion.

Consensus

The existence of a consensus within an academic community may be indicated, for example, by independent secondary or tertiary sources that come to the same conclusion. The statement that all or most scientists, scholars, or ministers hold a certain view requires a reliable source. Without it, 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.

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, while 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.

Other examples

See Wikipedia:Reliable source examples for examples of the use of statistical data, advice by subject area (including history, physical sciences, mathematics and medicine, law, business and commerce, popular culture and fiction), and the use of electronic or online sources.

External links

How to Read a Primary Source, Reading, Writing, and Researching for History: A Guide for College Students, Patrick Rael, 2004.
How to Read a Secondary Source, Reading, Writing, and Researching for History: A Guide for College Students, Patrick Rael, 2004.