This is an essay on the Featured article criteria. It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints.

Shortcuts WP:FARS WP:FACS WP:FASOURCE

Source checking is a critical part of the WP:FAC review process. The purpose of this essay is to help editors carry out effective source reviews; article authors may also find the advice helpful.

All Wikipedia articles should be based on reliable sources, but at FAC the bar is set higher. The featured-article criteria (FACR) require articles to be "a thorough and representative survey of the relevant literature" (point 1c), and sources to be not only reliable but of high quality (1c). In addition, the citations must be formatted consistently throughout (2c). It is the task of the source reviewer to see that these criteria are observed.

The concept of "high quality" has to be flexibly applied. In some areas—major historical events, biographies of world figures, etc.—the relevant literature is vast, and high-quality sources are plentiful. In other cases, particularly in the various fields of sport or popular culture, "high quality" often has to be interpreted as "best available".

At FAC it is practice to require that every material statement, unless self-evidently true, be supported by a citation, not only material likely to be challenged (per WP:V). Where a cited source does not support the text, that source should be replaced or the text altered to reflect what the source says.

Source reviewers are expected to make clear that they have fully evaluated the article on both the criteria given below:

• (1c): well-researched: it is a thorough and representative survey of the relevant literature; claims are verifiable against high-quality reliable sources and are supported by inline citations where appropriate;
• (2c): consistent citations: where required by criterion 1c, consistently formatted inline citations using either footnotes (<ref>Smith 2007, p. 1.</ref>) or Harvard referencing (Smith 2007, p. 1)

Reliability

All sources must comply with the sourcing policies: WP:V and WP:NOR. Material about living persons, whether in biographies or elsewhere, must comply with WP:BLP. All biomedical claims, in any article, should comply with WP:MEDRS; also see WP:MEDMOS for sourcing and formatting expectations in medical articles.

Reliability is a minimal requirement; not all reliable sources will meet the FA quality criterion. Reliability may also be a matter of judgement. In cases of doubt, the onus is on the nominator to show that a source should be considered reliable; hence the question that often occurs in source reviews: "What makes this source reliable"?

The sourcing policies, and the guideline Identifying reliable sources, require that sources be reliably published, either in print form (book, journal, newspaper), audio-visual form (film, video, etc.), or online. Published sources may be primary or secondary and, occasionally, tertiary. (See WP:PSTS for the distinctions.) Articles should, where possible, be based mainly on secondary sources, but the careful use of primary sources is entirely acceptable and even welcome. Tertiary sources are acceptable too, but the use of tertiary sources on a topic served by a large scholarly literature might be something to ask the nominator about.

The key factor in assessing reliability is the publisher. Examples of publishers typically considered reliable include:

• established commercial book publishers, particularly academic publishers;
• academic journals;
• most national and regional newspapers and magazines;
• news organisations such as Reuters and the Associated Press;
• broadcasting organisations such as the BBC and CNN;
• national or international expert bodies, such as the World Health Organization;
• governments and their agencies/departments;
• other public bodies or organisations, e.g. universities, museums, major libraries, professional bodies;
• industrial corporations and other private organisations as sources of information about themselves, but not otherwise (see WP:SPS).

The following are examples of sources not generally considered reliable:

• self-published material (such as books, blogs and personal websites), unless the author is a recognised published expert in the field; see WP:SPS, but also see WP:BLPSPS;
• tabloid journalism, although newspapers known for tabloid journalism may be used for the purpose of directly quoting an article subject;
• fansites.

High quality

In addition to the usual reliability requirement, the text of featured articles must be "verifiable against high-quality reliable sources". Reviewers with some expertise in the subject of the article will more easily be able to determine whether the sources used meet the required quality standard. The general questions on which all reviewers should try to satisfy themselves are:

• Do the sources represent the best available for this particular subject?
• Is the source that supports each point the most appropriate for that point?
• Are the main sources reasonably up-to-date, and therefore likely to represent the most recent scholarship? Older sources, particularly contemporaneous primary sources, are often appropriate, but the nominator may need to explain why they've been chosen.
• In the case of anything contentious, are primary sources being used in accordance with the secondary literature?
• Do the sources appear collectively to provide a comprehensive account of the subject, or is there over-reliance on a particular source or group of like-minded sources? Reviewers should be aware that even the highest-quality sources can be used selectively in a way that affects the neutrality of the article.

Making these judgements takes time, and raising them will sometimes invoke the ire of nominators, but if reviewers have any doubts about sources quality, individually or collectively, they should pursue the matter.

Verifiability

Every cited statement in an article must be capable of being checked from the source. This does not mean that they must be available to all online. Although verification is obviously easier for web-based sources, print sources must be ultimately verifiable to anyone willing to chase down a book or article. This means that books, newspapers, magazine and journal articles must be defined as precisely as possible; see the format section below.

Google Books links are often used for book sources. If Google Books makes the cited pages available, this is useful. Otherwise, the link may do nothing more than verify that the book exists. Some editors, nonetheless, are very fond of using them, but they are not essential.

Spot checking

Reviewers should carry out spot checks to ensure that sources have been used appropriately, that the sources do indeed support the text, and that the article contains no plagiarism, including close paraphrasing without in-text attribution. The extent to which spot checks are pursued is a matter for each reviewer. It is unreasonable to expect a reviewer to test each cited statement against its source; the volume of citations and the non-accessibility of many print sources make this infeasible. The FAC coordinators will usually require spot-checking for first-time nominations.

Sourcing information should be presented in a consistent and uniform style; the increasing use of cite templates has made this easier to check. This part of the review is the most mechanical, but it should not be skimped. Certain tools have been developed to assist this process, and some of these can be found in the toolbox which appears top right in every FAC nomination. (The external links checker^{[dead link]} claims to be "over 98% accurate".)

Basic format checks

• Books should be defined in terms of author, title, year and/or edition, and publisher. Publisher location and, where possible, ISBN are usually added, but they are not required by WP:CITE. Consistency requires that these optional fields are either added in all instances or omitted in all instances (except where a book does not have an ISBN).
• Page numbers: Check that "p." and "pp." are used appropriately; that page ranges include en dashes, not hyphens; that the ranges are presented consistently (use either 125–128 or 125–28; the MoS prefers 125–128); and that the ranges are not too long (e.g. pp. 150–200 should be questioned). Page ranges that are manually written need a non-breaking space after the p.
• Newspaper, magazine and journal sources require, minimally, the byline if there is one, the title of the article, the name of the publication, the date, a URL if online, and the page number if no link is provided. Other information should be provided if it is available: e.g. volume number, issue number. For journal articles, the digital object identifier is expected, and for medical sources the PMID. (See WP:MEDRS and WP:MEDMOS for sourcing and formatting requirements in medical articles.)
• Websites require, minimally, title, a working link, the name of the site, and a retrieval date. Information such as author and date of the item should be included if available. According to WP:LR: "Editors are encouraged to add an archive link as a part of each citation, or at least submit the referenced URL for archiving, at the same time that a citation is created or updated."
• For audio-visual or other less standard sources (e.g. conferences, legal cases, patents), it is best to consult the specialist templates created for these sources to ensure that the proper formats are created. See WP:CT.

Particular things to look out for

• Broken links: links that don't work or lead to a page other than that defined. You can only be sure of this by checking all links. Use ((Featured article tools)) for this purpose; place it on article talk or the FAC page.
• Inappropriate italics: this is a factor that confuses many editors. The names of newspapers, magazines and journals are italicised (e.g., The New York Times), but the names of publishers are not; newspaper and journal publishers are usually not included at all (e.g. The New York Times Company). Book titles are italicised (e.g. A Theory of Justice), but article titles are not (e.g. "Justice as Fairness"). Book publishers are included but not italicised (e.g. Oxford University Press). Correct italicisation follows naturally when ((cite newspaper)), ((cite journal)) and ((cite book)) are used. The main problem arises with the misuse of the work=, publisher=, and website= fields. The work is the title of the newspaper, magazine or journal (e.g. The New York Times). It is not the publisher. Thus, for example, work=CNN will, in a citation template, produce incorrect italicisation. Some editors include both work= and publisher= in their source details, but this is not generally necessary.
• Either ((cite)) or ((citation)) templates may be used, but they should not be mixed within the same article because their punctuation differs. More details at WP:CT.

If you have questions, please ask for help at WT:FAC.

Although written with FAC in mind, the principles may be usefully applied to other featured content, e.g. Wikipedia:Featured list candidates. Here are some useful links:

• Wikipedia:Featured articles
• Wikipedia:Featured article candidates
• Wikipedia:Featured article criteria
• User:Headbomb/unreliable for detecting sources that may not be reliable
• User:Ealdgyth/FAC, Sources, and You