Wikipedia:Citation overkill

Material that is repeated multiple times in an article does not require an inline citation for every mention. If you say an elephant is a mammal more than once, provide one only at the first instance.

Avoid cluttering text with redundant citations like this:

In addition, as per WP:PAIC, citations should be placed at the end of the passage that they support. If one source alone supports consecutive sentences in the same paragraph, one citation of it at the end of the final sentence is sufficient. It is not necessary to include a citation for each individual consecutive sentence, as this is overkill. This does not apply to lists or tables, nor does it apply when multiple sources support different parts of a paragraph or passage.

This is correct:

This is also correct, but is an example of overkill:

If consecutive sentences are supported by the same reference, and that reference's inline citation is placed at the end of the paragraph as described at WP:CITETYPE, an editor may want to consider using Wikipedia's hidden text syntax <!-- --> to place hidden ref name tags at the end of each sentence. Doing so may benefit others adding material to that paragraph in the future. If that happens, they can uncomment the hidden citations and switch to citing references after every sentence. Having hidden citations could cause confusion, especially among inexperienced editors, so the approach is strictly optional and should be used cautiously.

Another common form of citation overkill is to cite multiple reprintings of the same content in different publications – such as several different newspapers reprinting the same wire service article, or a newspaper or magazine article getting picked up by a news aggregator – as if they constituted distinct citations. Such duplicated citations may be piled up as multiple references for the same fact or they may be split up as distinct footnotes for different pieces of content, so watching out for this type of overkill may sometimes require special attention.

This type of overkill should be resolved by merging all of the citations into a single one and stripping unhelpful repetitions – when possible, the retained citation should be the originator of the content rather than a reprinter or aggregator, but if this is not possible (e.g. some wire service articles) then retain the most reliable and widely distributed available reprinter (for example, if the same article has been linked to both The New York Times and The Palookaville Herald, then The New York Times should be retained as the citation link.)

A similar case is redundant citation of an article that got its information from an article we have already cited. An exception, to many scientific and technical editors, is when we cite a peer-reviewed literature review and also cite some of the original research papers the review covers. This is often felt to provide better utility for academic and university-student users of Wikipedia, and improved verifiability of details, especially in medical topics. Similar concerns about the biographies of living people may sometimes result in "back-up" citations to original reportage of statements or allegations that are later repeated by secondary sources that provide an overview.

In controversial topics, sometimes editors will stack citations that do not add additional facts or really improve article reliability, in an attempt to "outweigh" an opposing view when the article covers multiple sides of an issue or there are competing claims. This is something like a PoV fork and edit war at once, happening inside the article's very content itself, and is an example of the fallacy of proof by assertion: "According to scholars in My School of Thought, Claim 1.^{[1][2][3][4][5]} However, experts at The Other Camp suggest that Claim 2.^{[6][7][8][9][10]}"

If this is primarily an inter-editor dispute over a core content policy matter (point of view, source interpretation, or verifiability of a claim), talk page discussion needs to proceed toward resolving the matter and balancing the article. If the dispute seems intractable among the regular editors of the article, try the requests for comments process; the applicable NPOV, NOR or RS noticeboard; or formal dispute resolution.

If the matter is the subject of real-world dispute in reliable sources, our readers actually need to know the conflict exists and what its parameters are (unless one of the conflicting views is a fringe viewpoint). Competing assertions with no context are not encyclopedic. Instead, the material should be rewritten to outline the nature of the controversy, ideally beginning with secondary sources that independently describe the conflicting viewpoints or data, with additional, less independent sources cited only where pertinent, for verification of more nuanced claims made about the views or facts as represented by the conflicting sources. Sources that are opinional in nature – op-eds, advocacy materials, and other primary sources – can usually simply be dropped unless necessary to verify quotations that are necessary for reader understanding of the controversy.

Contrary views (and approaches to addressing their concerns) include:

• A cited source usually contains further relevant information than the particular bit(s) it was cited for, and its removal may be thought to "deprive" the reader of those additional resources. Wikipedia is not a Web index, and our readers know how to use online search engines. In most cases, if a source would be somewhat or entirely redundant to cite for a particular fact, but has important additional information, it is better to use it to add these facts to the article. Or, if the additional material is not quite encyclopedically pertinent to the article but provides useful background information, add it to the "Further reading" or "External links" section instead of citing it inline in a way that does not actually improve verifiability.
• An additional citation may allay concerns of some editors that the text constitutes a copyright violation. This is usually a short-term issue, and is often better handled by discussing the evidence on the talk page, if the additional citation does not really increase verifiability (e.g., because the original citation, with which the added one would be redundant, is to a clearly reliable source, and there are no disputes about its accuracy or about the neutrality or nature of its use).
• As alluded to above, an additional citation may allay concerns as to whether the other citation(s) are sufficient, for WP:RS or other reasons. While this is often a legitimate rationale to add an additional source that some editors might consider not strictly necessary, it is sometimes more practical to replace weak sources with more reliable ones, or to add material outlining the nature of a disagreement between reliable sources. How to approach this is best settled on a case-by-case basis on the article's talk page, with an RfC if necessary, especially if the alleged fact, topic, or source is controversial. Adding competing stacks of citations is not how to address WP content disputes or real-world lack of expert consensus.

Using multiple sources to support a particular fact or sentence in an article is sometimes appropriate, provided that each source provides a distinct and useful insight, and the multiplicity of sources does not introduce any bias, confusion, or undue weight. But when there are an excessive number of citations, some should be removed. This can be accomplished by removing less significant sources, bundling citations (so they appear as a single footnote), restructuring sentences, or moving citations.

Each of these articles has been corrected. Links here are to previous versions where a citation problem existed.

• Iris graminea – 275 citations for one section out of 580 in the article, citing 44 unique sources
• Customs and Excise Department (Hong Kong) – 83 citations for one sentence, part of 139 citations in a single paragraph. Notably, the rest of the article remained largely uncited.
• China–United States trade war – 20 citations for one statement, after the phrase "advanced technology"
• Palestinian Christians – 65 citations in opening paragraph
• Carrfour Supportive Housing – 33 citations for one sentence
• Drifting (motorsport) – 29 citations for one sentence
• Howard Cosell – 20 citations for one sentence, 3 of which were YouTube
• Alvin Duskin – 77 citations for an article not even 70 words in length
• William Selig – 22 citations for one sentence
• Electrical Transient Analyzer Program – 33 academic citations for lists of features and uses
• If (magazine) - 20 citations for a short paragraph about a new magazine

• {{Excessive citations}}
• {{Excessive citations inline}}

• Wikipedia:Citation underkill – An essay with a contrary viewpoint suggesting to cite every sentence/statement
• Wikipedia:Wisps' Law
• Wikipedia:You don't need to cite that the sky is blue
• Wikipedia:Masking the lack of notability
• Wikipedia:Overlink crisis
• mw:Extension:HarvardReferences – extension to improve references into Harvard style
• Wikipedia:Why most sentences should be cited
• Category:Citation overkill, for Wikipedia articles that display a case of citation overkill
• Wikipedia:Must I add a citation? – What should one do on finding a correct but uncited statement in an article.
• Wikipedia:Citation Emergency (humorous essay)
• Wikipedia:Contort the citations