Innovative application for the template in xkcd 285 (Wikipedian Protester)
The {{Citation needed}} template aims to promote accountable discourse.

To ensure that all Wikipedia content is verifiable, anyone may question an uncited claim. If your work has been tagged, please provide a reliable source for the statement, and discuss if needed.

In wiki markup, you can question an uncited claim by inserting a simple {{Citation needed}} tag, or a more comprehensive {{Citation needed|reason=Your explanation here|date=May 2019}} clause ({{fact}} and {{cn}} will produce the same result). This displays as:

Example: 87% of statistics are made up on the spot.[citation needed]

"Citation needed" statements are part of Wikipedia's backlog of outstanding problems. Currently there are 358,962 articles with "Citation needed" statements (see the historical number of tags). You can help reduce the backlog!

When and how to use this tag

A "citation needed" tag is a request for another editor to verify a statement: a form of communication between members of a collaborative editing community. It is never, in itself, an "improvement" of an article. Though readers may be alerted by a "citation needed" that a particular statement is not supported, many readers don't fully understand the community's processes. Not all tags get addressed in a timely manner, staying in place for months or years, forming an ever growing Wikipedia backlog—this itself can be a problem. Best practice recommends the following: