|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
|This page in a nutshell: Wiki projects do not rise to the level of a reliable secondary source unless unusual measures are taken to certify versions for this purpose|
The question frequently comes up whether Wikipedia, other WMF projects, or special projects such as the WP:Wikipedia Signpost can be cited in articles as reliable sources.
As primary sources, these are indeed reliable, as the software quite reliably documents conversations, with the talk page history demonstrating that a particular account said something at a precise time. However, see WP:BLPPRIMARY, which prohibits use of primary sources on their own to source claims about living people in articles. Interpretation of primary sources by editors is often problematic anyway.
However, as secondary sources, Wikis are generally questionable in nature, because they lack consistent fact-checking and meaningful editorial oversight. The reason for this is in the way a Wiki is edited. Each person who makes a change to an article is responsible for the edit he makes - but he does not have a beginning-to-end responsibility for everything written in the article. A three-paragraph article may be the work of one user for the first, another for the second, and another for the third. Additionally, we do not know for sure that all editors lack a conflict of interest, whether it be financial or merely an intent to vandalize rather than edit responsibly.
Upgrading an article to a reliable secondary source
A number of suggestions have been made for ways to certify Wikipedia, at WP:Stable versions, Meta:Article validation feature and Meta:Reviewed article version. Other ideas at WP:Flagged revisions and WP:Pending Changes regard ideas to get a second editor to verify individual edits, but generally do not involve full independent verification of all claims in every edit. Nonetheless, a procedure to do so can be carried out with very little technical sophistication - but it is demanding.
To certify a Wikipedia article version as a reliable secondary source,
- Gather several persons who are recognized as competent professionals in the relevant field, who are willing to post their approval of a specific version under their own names.
- Revise the article to remove all errors by normal Wiki editing.
- Cite the URL of a final "submitted" version from the article history.
- Each author must go over this version fully, beginning to end, and be willing to sign off on it in its entirety as if it were his own work. He must have access to all sources, including offline sources, whether by good library access, Wikipedia:WikiProject Resource Exchange, or less formal methods of sharing. Note that because authors are not generally accustomed to plagiarism, signing off on a hodgepodge of Wikipedia material as if it were their own may be a difficult thing for them to do.
- Optionally, enlist additional peer reviewers who have not previously been involved in the writing to do the same, elevating the version to "peer reviewed" status.
- Publish a simple statement, perhaps on the authors' personal web site(s), attesting to the version's passage of this process.
- The statement, and by extension the article (which it may incorporate) can now be used as a reliable source.
Note, however, that many authors will feel more comfortable simply to write their own text, incorporating some portions of a Wikipedia article, giving proper credit, or perhaps only its reference list, which would provide an easier alternative to this process.