 | To contact a checkuser about sensitive matters, see Contacting a checkuser. Otherwise, to open an investigation, go to Wikipedia:Sockpuppet investigations. |
 | This page documents a procedural policy of Wikipedia. It documents various processes by which the English Wikipedia operates. This local policy supplements—but cannot override—the global community CheckUser policy. |
The CheckUser tool is used by a small group of trusted Wikipedia users (called checkusers). The tool allows its users to determine from Wikipedia's servers the IP addresses used by a Wikipedia user account, as well as other technical data stored by the server about a user account or IP address.
Wikipedia's checkuser team uses the tool to establish whether two or more accounts are being operated by one individual or group of people, and to protect Wikipedia against disruptive or abusive behaviour.
Checkusers are able to view a list of all IP addresses used by a user account to edit the English Wikipedia, a list of all edits made by or from an IP address or range (which includes edits by accounts while on the IP address or range), or a list of all user accounts that have used an IP address or range. They may also view a log of CheckUser actions at Special:CheckUserLog.
CheckUser data is never accessed or released except in accordance with the Wikimedia Foundation's (WMF) privacy policy and the additional restrictions placed by this policy. After completing an investigation with the CheckUser tool, most checkusers release their findings in generalised form (such as with a statement that "account A is, is not, or may be the same as accounts B or C"); on the English Wikipedia, the release of actual private data (like "account D is connecting through IP address 0.1.2.3") is exceptionally rare. Conclusions derived from CheckUser data have limited usefulness, and a negative finding by a checkuser rarely precludes obvious sockpuppetry.
On the English Wikipedia, CheckUser access is entrusted to a restricted number of trusted users who can execute CheckUser inquiries at their own discretion. The permission is granted by Wikipedia's Arbitration Committee, after community consultation and vetting of the editor by the committee's members and the functionary team. While there is no formal requirement that checkusers also be administrators, the Arbitration Committee has traditionally restricted applications to users who are currently administrators. Checkusers must be 18 years of age or older and have signed the Wikimedia Foundation's confidentiality agreement for nonpublic information before being appointed. The use of the CheckUser tool on the English Wikipedia is monitored and controlled by the Arbitration Committee, and checkusers may have their permissions revoked by the Arbitration Committee for misuse or abuse of the tool.
This policy supplements the global checkuser policy and applies only to the English Wikipedia.