Wikipedia:Reliable sources: Difference between revisions
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Pmanderson (talk | contribs) Restore compromise version from Revert Warrior; if Itayb finds this redundant too, fine. |
This seems the clearest and most concise version - KISS is important in policiies |
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BEFORE ADDING MATERIAL TO THIS PAGE, PLEASE CHECK THAT IT IS NOT ALREADY INCLUDED IN [[Wikipedia:Verifiability]] OR [[Wikipedia:No original research]], WHICH ARE THE POLICY PAGES ON SOURCES. REPETITION IS POINTLESS, AND INCONSISTENCY IS WORSE THAN POINTLESS. MANY THANKS.--> |
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{{Wikipedia:Reliable sources/Header}} |
{{Wikipedia:Reliable sources/Header}} |
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{{guideline|WP:RS}} |
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===Scholary and non-scholarly sources=== |
===Scholary and non-scholarly sources=== |
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Wikipedia welcomes material written by scientists, scholars, and researchers, particularly material published by peer-reviewed journals. However, these may be outdated by more recent research, or may be controversial in the sense that there are alternative scholarly and non-scholarly treatments. Wikipedia articles should therefore ideally rely on all majority and significant-minority treatments of a topic, scholarly and non-scholarly, so long as the sources are reliable. |
Wikipedia welcomes material written by scientists, scholars, and researchers, particularly material published by peer-reviewed journals. However, these may be outdated by more recent research, or may be controversial in the sense that there are alternative scholarly and non-scholarly treatments. Wikipedia articles should therefore ideally rely on all majority and significant-minority treatments of a topic, scholarly and non-scholarly, so long as the sources are reliable. |
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===Scholarship=== |
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Wikipedia relies heavily upon the established literature created by scientists, scholars and researchers around the world. Items that fit this criterion are usually considered reliable. However, they may be outdated by more recent research, or controversial in the sense that there are alternative scholarly explanations. Wikipedia articles should point to all major scholarly interpretations of a topic. |
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* The material has been thoroughly vetted by the scholarly community. This means published in peer-reviewed sources, and reviewed and judged acceptable scholarship by the academic journals. |
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* Items that are recommended in scholarly bibliographies are preferred. |
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* Items that are signed are more reliable than unsigned articles because it tells whether an expert wrote it and took responsibility for it. |
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===Non-scholarly sources=== |
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Some criteria that can assist editors in evaluating non-scholarly sources: |
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*'''Attributability'''—The more we know about the originator, either organisation or individual, of source material, the better. This helps us measure the authority of the content. |
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*'''Expertise''' of the originator about the subject—An academic expert in one subject is more reliable when writing about that subject than when writing about another. For example, a biologist is more reliable when writing about biology than when writing about nuclear physics. |
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*'''Bias''' of the originator about the subject—If an author has some reason to be biased, or admits to being biased, this should be taken into account when reporting his or her opinion. This is not to say that the material is not worthy of inclusion, but please take a look at our policy on [[WP:NPOV|Neutral point of view]]. |
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<span id="editorial_oversight"></span> |
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*'''Editorial oversight'''—A publication with a declared editorial policy will have greater reliability than one without, since the content is subject to verification. ''Self published sources'' such as personal web pages, personally published print runs and blogs have not been subject to any form of independent fact-checking and so have lower levels of reliability than published news media (e.g. [[The Economist]]) and other sources with ''editorial oversight'', which is less reliable itself than professional or ''peer reviewed'' journal (e.g. [[Nature (journal)|Nature]]). |
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*'''Replicability'''—The conclusions of the source can be reached using the information available and there is no indication of gaps in the thinking or process of derivation. Essentially, this criterion asks if there are any ''leaps of faith'' in the source. |
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*'''Declaration of sources'''—A source which is explicit about the data from which it derives its conclusions is more reliable than one which does not. Ideally, a source should describe the collection process and analysis method. |
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*'''Confidentiality'''—Sources which are considered ''confidential'' by the originating publisher may hold uncertain authority. Given that the original cannot be used to validate the reference, these should be treated with caution. |
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*'''Corroboration'''—The conclusions match with other sources in the field which have been derived independently. If two or more independent originators agree, in a reliable manner, then the conclusions become more reliable. Care must be taken to establish that corroboration is indeed independent, to avoid an invalid conclusion based on uncredited origination. |
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* '''Recognition by other reliable sources'''—A source may be considered more reliable if another source which is generally considered reliable cites or recommends it. Sources which have been attacked, or have rarely or never been cited, may be more suspect. |
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*'''Age of the source and rate of change of the subject'''—Where a subject has evolved or changed over time, a long standing source may not be accurate with respect to the current situation. To interpret utility one must appreciate how the subject has changed and if that change has impacted any of the salient points of the source information. Historical or out-of-date sources may be used to demonstrate evolution of the subject but should be treated with caution where used to illustrate the subject. If no newer sources are available, it is reasonable to caveat use of sources with an indication of the age and the resulting reduction in reliability. |
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*'''Persistence'''— If a reader goes to the cited source to validate a statement, or to gain further understanding of the topic, the form cited should remain stable, continuing to contain the information used by the editor to support the words. In this sense a book or journal citation is superior to an online source where the link may become ''broken''. Some web resources have editorial policies which lead to a lack of persistence; therefore, web citations should be treated with caution. |
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These issues are particularly pertinent to Wikipedia where various editors involved in an article may have their own expertise or position with respect to the topic. Not all sources on a topic are equally reliable, and some sources will have differing degrees of reliability in different contexts. |
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In general, a topic should use the most reliable sources available to its editors. [[Wikipedia:Use common sense|Common sense]] is required to determine what sources to use; this guideline cannot be applied robotically. If you have questions about a source's reliability, discuss with other editors on the article's talk page, or if the source is already used in the article, you can draw attention to it with the {{Tl|unreliable}} template. |
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=== Exceptional claims require exceptional sources === |
=== Exceptional claims require exceptional sources === |
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===Types of source material=== |
===Types of source material=== |
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:See ''[[Wikipedia:No original research#Primary, secondary, and tertiary sources]]'' |
:See ''[[Wikipedia:No original research#Primary, secondary, and tertiary sources|No original research: Primary, secondary, and tertiary sources]]'' |
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Three classes of sources exist, each of which can be used within Wikipedia: |
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*A '''[[primary source]]''' is a document or person providing direct evidence of a certain state of affairs; in other words, a source very close to the situation you are writing about. Primary sources include official reports, letters, eyewitness accounts, autobiographies, statistics compiled by authoritative agencies, court records, or other documents produced by a participant in an event, or an observer of an event. Primary sources that have been published by a reliable source may be used in Wikipedia, but only with care, because it's easy to misuse them. For that reason, anyone—without specialist knowledge—who reads the primary source should be able to verify that the Wikipedia passage agrees with the primary source. Any interpretation of primary source material requires a secondary source because experts have the resources required for interpretation, interpolation, extrapolation, or corroboration, each of which usually constitutes [[Wikipedia:No original research|original research]]. |
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*'''[[secondary source| Secondary]]'''—The informed and expert interpretation, interpolation, extrapolation or corroboration of primary sources to synthesize a conclusion. In general, Wikipedia articles should rely on reliable secondary sources. |
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*'''[[tertiary source| Tertiary sources]]''' are reference books such as dictionaries, general encyclopedias and almanacs. These sources generally lack adequate coverage of the topic to be considered comprehensive where arguments are subtle and nuanced. They generally do not discuss and evaluate alternative interpretations. Tertiary sources used for basic facts such as names, spellings, locations, dates and dimensions do not need to be cited. Tertiary sources used for more substantive facts do need to be cited. Some tertiary sources are more reliable than others, and within any given tertiary source, some articles may be more reliable than others. For example, articles signed by experts in ''Encyclopaedia Britannica'' and encyclopedias of similar quality can be regarded as reliable secondary sources instead of tertiary ones. Unsigned articles may be less reliable, but they may be used so long as the encyclopedia is a high quality one. |
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Often the reliability of a source is not determined by its type, but by how it is used. For example, the diary of a famous politician (a primary source) would probably be reliable as source for a statement of opinion, but might not be reliable as a source for a statement of fact. |
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==Biographies of living persons== |
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:{{main|[[Wikipedia:Biographies of living persons]]}} |
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Wikipedia articles that present material about living people can affect subjects' lives. Biographical material must be written with the greatest care and attention to [[WP:V|verifiablilty]] and [[WP:NPOV|neutrality]], particularly if it is contentious.<ref>Jimmy Wales about "Zero information is preferred to misleading or false information" [http://mail.wikimedia.org/pipermail/wikien-l/2006-May/046440.html] [http://mail.wikimedia.org/pipermail/wikien-l/2006-May/046730.html] [http://mail.wikimedia.org/pipermail/wikien-l/2006-May/046732.html] [http://mail.wikimedia.org/pipermail/wikien-l/2006-May/046733.html]</ref> |
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Due to the legal sensitivity of these articles as well as moral obligations, do not include anything on living persons, if you cannot find a verifiable secondary source to rely on. |
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==Self-published sources (online and paper)== |
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{{shortcut|WP:SPS|WP:SELFPUB}} |
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:''See the section in the policy: [[Wikipedia:Verifiability#Self-published sources (online and paper)|Verifiability: Self-published sources (online and paper)]]'' |
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A self-published source is a published source that has not been subject to any form of independent fact-checking, or where no one stands between the writer and the act of publication. It includes personal websites and books published by [[vanity press]]es. Anyone can create a website or pay to have a book published, and then claim to be an expert in a certain field. For that reason, self-published books, personal websites, and [[Weblog|blogs]] are usually not acceptable as sources (see Exceptions below). |
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===Self-published sources as secondary sources=== |
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'''Personal websites, blogs, and other self-published or vanity publications should not be used as secondary sources.''' That is, they should not be used as sources of information about a person or topic other than the owner of the website, or author of the book. The reason personal websites are not used as secondary sources is that they are usually created by unknown individuals who have no one checking their work. They may be uninformed, misled, pushing an agenda, sloppy, relying on rumor and suspicion, or even insane; or they may be intelligent, careful people sharing their knowledge with the world. Only with independent verification by other sources not holding the same POV is it possible to determine the difference. |
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===Exceptions=== |
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As mentioned above there are a few specific situations in which a self-published source can be considered reliable. These include: |
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When a '''well-known, professional researcher writing within his or her field of expertise''', or a well-known professional journalist, has produced self-published material, these ''may'' be acceptable as sources, so long as his or her work has been previously published by credible, third-party publications. Editors should exercise caution for two reasons: first, if the information on the professional researcher's blog (or self-published equivalent) is really worth reporting, a reliable source will probably have covered it; secondly, the information has been self-published, which means it has not been subject to independent fact-checking. In general it is preferable to wait until other sources have had time to review or comment on information found in self-published sources. |
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Government officials self-publishing within the scope of their official duties, and using official government channels, but without editorial oversight, are also acceptable primary sources for reporting on the official acts of that person or group. |
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===Self-published sources used as primary sources about themselves=== |
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Self-published material, whether published online or as a book or pamphlet, may be used as a primary source of information about the author or the material itself, so long as there is no reasonable doubt who wrote the material, and so long as it is: |
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* relevant to the self-publisher's notability; |
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* not contentious; |
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* not unduly self-serving or self-aggrandizing; |
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* about the subject only and not about third parties or events not directly related to the subject; |
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The reputation of the self-publisher is a guide to whether the material rises to the level of notability at all. |
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== Bulletin boards, wikis and posts to Usenet == |
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Posts to bulletin boards, Usenet, and wikis, or comments on blogs, should generally not be used as sources. This is in part because we have no way of knowing who has written or posted them, and in part because there is no editorial oversight or third-party fact-checking. See [[#Self-published sources|self-published sources]] for exceptions. |
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Some known exceptions include. |
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* [[Wikinews]]: a project dedicated to generating reliable content for wikipedia based on their own research. Do make sure to check an article thoroughly before using it as a reference. |
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* Certain usenet posts (such as generally recognised official newsgroup faqs, and posts to particular administrative groups) may well be reliable sources in articles about usenet itself. <small>You could consider them self-published sources, in this context.</small> |
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* [[Wikisource]]: A project to archive sources that are currently freely available. (including PD, out of copyright, and published-as-free-content sources). (See also under [[#Convenience links]].) |
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== Partisan, corporate, institutional and religious sources == |
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{{see also|Wikipedia:Neutral point of view}} |
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The websites, print media, and other publications of political parties, companies, organizations and religious groups should be treated with caution, since they may be used to advance particular political, corporate, institutional or religious viewpoints. Of course such political, corporate, institutional or religious affiliation is not in itself a reason to exclude a source. |
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===Biographies of living persons=== |
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Caution should be used when using company or organization websites as sources. Although the company or organization is a good source of information on itself, it has an obvious bias. The American Association of Widget Manufacturers is interested in promoting widgets, so be careful not to rely on it exclusively if other reliable sources are available, in order to maintain [[WP:NPOV|a neutral point of view]]. Exercise particular care when using such a website as a source if the company or organization is a controversial one. |
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:''See [[Wikipedia:Biographies of living persons]]'' |
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== |
===Self-published sources (online and paper)=== |
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:''See [[Wikipedia:Verifiability#Self-published sources (online and paper)|Verifiability: Self-published sources (online and paper)]]'' |
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Organizations and individuals that are widely acknowledged as extremist, whether for political, religious or anti-religious, racist, or other extremism, produce literature which is often defensive and rarely reviewed by any independent authority. It is normally of extremely limited reliability, except perhaps on the group itself; even there, claims about the groups' history and purpose are often non-consensus. Use with caution; and see also [[WP:FRINGE]]. |
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===Extremist sources=== |
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Do remember, however, that "extremist" is a common pejorative. Deciding that a group is extremist should require the same wide consensus of authority as making an assertion as a fact, in Wikipedia's voice. |
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Organizations and individuals that are widely acknowledged as extremist, whether of a political, religious or anti-religious, racist, or other nature, should be used only as sources about themselves and their activities '''in articles about themselves''', and even then with caution. |
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==Claims of consensus== |
===Claims of consensus=== |
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Claims of consensus must be sourced. The claim that all or most scientists, scholars, or |
Claims of consensus must be sourced. The claim 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. |
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==Convenience links== |
==Convenience links== |
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Revision as of 16:13, 16 April 2007
 | This page documents an English Wikipedia WP:RS. Editors should generally follow it, though exceptions may apply. Substantive edits to this page should reflect consensus. When in doubt, discuss first on this guideline's talk page. |
Wikipedia articles should be based on reliable, published sources. This page is a guideline, not a policy, and is mandatory only insofar as it repeats material from policy pages. The relevant policies on sources are Wikipedia:Verifiability, Wikipedia:No original research, and Wikipedia:Neutral point-of-view.
Wikipedia:Verifiability says that any material that is challenged or likely to be challenged needs a source, as do quotations, and the responsibility for finding a source lies with the person who adds or restores the material. Unsourced or poorly sourced edits may be challenged and removed at any time. Sometimes it is better to have no information at all than to have information without a source. See that page for more information about Wikipedia's policy on sourcing.
Why use reliable sources?
Sources are used:
- To support an assertion made in an article. Sources used in this manner should be directly referenced for the point that is being supported.
- To give credit to the source, to avoid the appearance of plagiarism or copyright violations. See Wikipedia:Copyrights.
Using reliable sources assures the reader that what is being presented meets the Wikipedia standards for verifiability, originality, and neutrality. Accurate citation allows the reader to go to those sources and gives appropriate credit to the author of the work.
Assessing the reliability of the sources used in an article allows the editor to caveat the statements made, identifying where weaknesses are present and where there may be alternative positions on a statement, with a qualitative opinion presented on the relative arguments based on the quality of sources.
If all the sources for a given statement or topic are of low reliability, this suggests to the reader that the content be treated with a degree of skepticism, and to the editor that the material may not be suitable for inclusion in Wikipedia.
Aspects of reliability
Scholary and non-scholarly sources
Wikipedia welcomes material written by scientists, scholars, and researchers, particularly material published by peer-reviewed journals. However, these may be outdated by more recent research, or may be controversial in the sense that there are alternative scholarly and non-scholarly treatments. Wikipedia articles should therefore ideally rely on all majority and significant-minority treatments of a topic, scholarly and non-scholarly, so long as the sources are reliable.
Exceptional claims require exceptional sources
Certain red flags should prompt editors to examine the sources for a given claim.
- Surprising or apparently important claims that are not widely known.
- Surprising or apparently important reports of recent events not covered by reputable news media.
- Reports of a statement by someone that seems out of character, embarrassing, controversial, or against an interest they had previously defended.
- Claims not supported or claims that are contradicted by the prevailing view in the relevant academic community. Be particularly careful when proponents say there is a conspiracy to silence them.
Exceptional claims should be supported by multiple credible and verifiable sources, especially with regard to historical events, politically-charged issues, and biographies of living people.
Types of source material
Biographies of living persons
Self-published sources (online and paper)
Extremist sources
Organizations and individuals that are widely acknowledged as extremist, whether of a political, religious or anti-religious, racist, or other nature, should be used only as sources about themselves and their activities in articles about themselves, and even then with caution.
Claims of consensus
Claims of consensus must be sourced. The claim 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.
Convenience links
Also see Wikipedia:Convenience links
The term "convenience link" is typically used to indicate a link to a copy of a resource somewhere on the Internet, offered in addition to a formal citation to the same resource in its original format. For example, an editor providing a citation to Adam Smith's famous work The Wealth of Nations might choose to include both a citation to a published copy of the work and a link to the work on the internet, as follows:
Smith, Adam (1904) [1776]. ed. Edwin Cannan (ed.). The Wealth of Nations (Fifth edition ed.). London: Methuen and Co.
{{cite book}}:|edition=has extra text (help);|editor=has generic name (help), available at Wikisource
Such links are unique in how reliability is applied. It is important to ensure that the copy being linked is a true copy of the original, without any comments, amendations, edits or changes. When the "convenience link" is hosted by a site that is considered reliable on its own, this is relatively easy to assume. However, when such a link is hosted on a less reliable site, the linked version should be checked for accuracy against the original, or not linked at all if such verification is not possible.
Examples of statistics, subjects, and online sources
See Wikipedia:Reliable sources/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.
See also
- Wikipedia:Check your facts, essay
- Wikipedia:Common knowledge, essay
- Wikipedia:Independent sources, essay
- Wikipedia:WikiProject Fact and Reference Check
- Wikipedia:Verifiability
- Wikipedia:No original research
- Wikipedia:Citing sources
References
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.