Dâ Wikipedia, la nciclupidìa lìbbira.
Green check.png This page documents an official policy on the English Wikipedia. The main Wikimedia Foundation policy on CheckUser has been decided on Meta (m:CheckUser#Policy) and nothing here may override that policy without approval there.


Please see Wikipedia:Requests for CheckUser for how to request CheckUser intervention.

On Wikipedia, CheckUser is a tool allowed to be used by a small number of users who are permitted to examine user IP information and other server log data under certain circumstances, for the purposes of protecting Wikipedia against actual and potential disruption and abuse. Checkuser itself simply produces log information for checking; it can require considerable skill and experience to investigate cases even with the tool.

On the English Wikipedia, CheckUser is entrusted to a restricted number of users, who can both execute CheckUser inquiries subject to the requirements below, and monitor and crosscheck each other's use of the function.

The permission is approved (exceedingly rarely and only with good cause) by the Arbitration Committee, who handle many privacy-related functions. Users authorized for CheckUser must be 18 or over, and have provided personal identification to the Wikimedia Foundation.


Template:Main The CheckUser feature is approved for use to prevent disruption, or investigate legitimate concerns of bad faith editing. The Wikimedia Foundation policy on CheckUser reads as follows:

Grounds for checking[cancia]

The tool is to be used to fight vandalism, to check for sockpuppet abuse, and to limit disruption of the project. It must be used only to prevent damage to any Wikimedia project.

The tool should not be used for political control; to apply pressure on editors; or as a threat against another editor in a content dispute. There must be a valid reason to check a user. Note that alternative accounts are not forbidden, so long as they are not used in violation of the policies (for example, to double-vote or to increase the apparent support for any given position).

Notifying the account that is checked[cancia]

Notification to the account that is checked is permitted but is not mandatory. Similarly, notification of the check to the community is not mandatory, but may be done subject to the provisions of the privacy policy.

Some wikis allow an editor's IPs to be checked upon his or her request if, for example, there is a need to provide evidence of innocence against a sockpuppet allegation; note, however, that requesting a checkuser in these circumstances is sometimes part of the attempt to disrupt.
[Note: English Wikipedia does not usually undertake such checks on request]

CheckUser and privacy policy[cancia]

Template:Main The CheckUser feature accesses non-public information. The Wikimedia Foundation takes privacy of its editors extremely seriously, and there may at times be a conflict between the high priorities given to both protecting the Wiki from damage and disruption, and privacy of even problematic users. This is a very delicate area and at times no solution is ideal; the following cover some of the principles and common practices on English Wikipedia. If in doubt please ask an experienced CheckUser.

  1. CheckUsers have a wide range of discretion to use their access provided it is for legitimate purposes – broadly, those which relate to preventing or reducing potential or actual disruption, and to investigation of legitimate concerns of bad faith editing. (CheckUser policy)
  2. CheckUsers may accept requests publicly or otherwise, as they see fit.
  3. Requests should not be accepted on the basis of "fishing" - that is, requests by users without a good and specific cause. On their own cognisance they may however perform privately as part of their role, any checks within the bounds of CheckUser policy - that is to say, any check which is reasonably performed in order to address issues of disruption or damage to the project.
  4. Disclosure of CheckUser results is subject to privacy policy, which broadly states that identifying information should not be disclosed under any but a few circumstances. These include:
    • "With permission of the affected user",
    • "Where the user has been vandalising articles or persistently behaving in a disruptive way, data may be released to assist in the targeting of IP blocks, or to assist in the formulation of a complaint to relevant Internet Service Providers", and
    • "Where it is reasonably necessary to protect the rights, property or safety of the Wikimedia Foundation, its users or the public."

IP information disclosure[cancia]

It is not normally considered a breach of privacy policy to state that different named accounts are operated from the same IP or range if details of the range are not given, or if a generic description only is given (country, large ISP etc) that in no way is very likely to identify a specific person. It is undesirable to link an IP to a named account, since an IP is often much more tightly linked to a specific person. (This is often less so for larger IP ranges: the larger the range, the less obvious the connection will often be to any specific person.) CheckUsers will employ a variety of means to avoid doing this, but in some cases it is hard to avoid and "Wikipedia norms are not a suicide pact" -- a user who is disruptive and needs to be addressed as such may have to accept that the price of disruption is that their IP becomes linked to their account.

This can happen in several ways:

  • A user is disruptive through multiple IPs, or a mixture of IPs and accounts. It is hard to block all of these (often on the same article) without obvious inference being drawn by onlookers.
  • A user is disruptive on multiple accounts, and it is reasonably plausible they will create more accounts, requiring the blocking of the underlying IP range that these accounts are using.

CheckUsers will often use a variety of techniques to avoid drawing such connections (new checkusers should ask and pick these up), but in many cases it is hard to avoid in a practical sense. Users who engage in problematic conduct to the point that requests for administrative action or blocking are raised and considered valid for CheckUser usage, and where Checkuser then determines that the user probably has engaged in such conduct, must expect that the protection of the project is given a higher priority than the protection of those who knowingly breach its policies on editorial conduct, if the two conflict or there is a problematic editing history.

IP information retention[cancia]

As configured by Wikimedia, Checkuser keeps IP and other information on users for a certain time only, to prevent abuse of older information. In general if a matter is not current, it is less likely to require administrative intervention.

Guidance given to CheckUsers[cancia]

m:CheckUser policy gives this guidance on privacy compliance:

Even if the user is committing abuse, it's best not to reveal personal information if possible.
  • Generally, do not reveal IPs. Only give information such as same network/not same network or similar. If detailed information is provided, make sure the person you are giving it to is a trusted person and will not reveal it himself.
  • If the user has said they're from somewhere and the IP confirms it, it's not releasing private information to confirm it if needed.
  • If you're in any doubt, give no detail. (m:Help:Checkuser states, "If you're in any doubt at all, give no detail and answer like a magic 8-ball.")

A further norm on English Wikipedia is: if you are requested to perform a check, always ask for the evidence of the user that a check is needed and appropriate, and confirm for yourself that there is indeed a valid basis that you can explain if needed. Do not assume, no matter who asks.

CheckUser operation[cancia]



A user with CheckUser access will get an extra "CheckUser" option under Special:SpecialPages.

Hints and tips[cancia]

Template:Main CheckUser's help page gives the following tips to users:

  • Checkuser is a technical tool, and requires a significant degree of familiarity with IPs, IP ranges, and related principles, to be correctly used.
  • CheckUser is not magic wiki pixie dust. Almost all queries about IPs will be because two editors were behaving the same way or an editor was behaving in a way that appears suggestive of possible disruption. An editing pattern match is the important thing; the IP match is really just extra evidence (or not).
  • Most dialup and a lot of DSL and cable IPs are dynamic. They might change every session, every day, every week, every few months or hardly ever. Unless the access times are right next to each other, be cautious in declaring a match. After a while, you get to know which ISPs change fast or slow. If it's a proxy, it might not be a match, depending on the size of the organisation running the proxy (per whois output). If it's an ISP proxy, it is not so likely to indicate a match. (Note - some users, particularly those involved in technical matters, can help identify whether an IP is likely to be a proxy, or is likely to be static, fast, or slow changing.)
  • There is both a checkuser mailing list (, and a checkuser irc channel (#wikimedia-checkuser), providing means to consult and get advice on checks and their interpretation, especially in the case of more complex vandalism. Both are used by checkusers on all Wikimedia Foundation projects; they are not just for the English Wikipedia.

Reasons and communication[cancia]

CheckUsers are expected to have policy-compliant grounds for Checkuser actions, identification, and blocks, and to discuss openly and fully with other CheckUsers their rationale if asked.


CheckUser requests are logged privately with a comment for each. The full log of all searches is visible to other CheckUsers at Special:CheckUser. The log lists who made a request, when, what the request was, and a provided comment. They do not list the results of the check, nor do they store any user IP data.

Assignment and revocation[cancia]


This section, in a nutshell;
This section is currently not set in stone. Those users who think that they have need of CheckUser must contact the Committee (or an individual member) first and proceed from there. However, be aware that typically only around 1–2 such appointments are made per year.

Users who require the CheckUser permission are typically members of the Arbitration Committee and former Arbitration Committee members. For those users who are not, in order to be approved for the CheckUser flag, a case should be made and sent to the ArbCom mailing list or to any active Arbitrator. Users are advised to initially sound out interest, discuss suitability, and check the current position via an off-list email to any active Arbitration Committee member, understanding that most times, new Checkusers are not being looked for. Appointments that are confirmed by the Arbitration Committee will be posted on Requests for permission on Meta-Wiki, a Steward will assign the permission once identification is confirmed.

Just as easily as the CheckUser permission can be approved, it can be revoked. If the Committee feels that an editor has abused CheckUser, such as by performing checks which do not qualify under one of the above criteria or inappropriately disclosing privacy related information from a CheckUser inquiry, they will immediately request a Steward to remove the permission from the editor. This may be done by any of the usual ways, including e-mail or a request on requests for permission on Meta.

Emergency requests based upon clear evidence may also be made in exceptional circumstances, the same way. In an exceptional case, and for good cause, a Steward may temporarily remove the permission, pending a decision by the Committee. The Steward should check the matter is well founded, and make clear immediately that it is a temporary response only, since such an action could lead to controversy.

Complaints and misuse[cancia]

Template:Main WMF policy on removal states that:

Any user account with CheckUser status that is inactive for more than a year will have their CheckUser access removed.

In case of abusive use of the tool, the Steward or the editor with the CheckUser privilege will immediately have their access removed. This will in particular happen if checks are done routinely on editors without a serious motive to do so (links and proofs of bad behavior should be provided).

Suspicion of abuses of CheckUser should be discussed by each local wiki. On wikis with an approved ArbCom, the ArbCom can decide on the removal of access... Removal can only be done by Stewards. A Steward may not decide to remove access on their own, but can help provide information necessary to prove the abuse (such as logs). If necessary, and in particular in case of lack of respect towards the privacy policy, the Board of [the] Wikimedia Foundation can be asked to declare removal of access as well.

Complaints of abuse of CheckUser or privacy policy breaches may also be brought to the Ombudsman committee.

The Ombudsman usually considers breaches of privacy policy. On English Wikipedia, complaints about misuse that do not result in privacy breaches should therefore be referred to the Arbitration Committee initially.

Users with CheckUser permissions[cancia]

An automatic list is available at Special:Listusers/checkuser. Accurate as of 25 August 2008, the CheckUser team is:

Current Arbitrators 
Deskana, FayssalF, FloNight, FT2, Jdforrester, Jpgordon, Kirill Lokshin, Morven, Newyorkbrad, Thebainer, UninvitedCompany, Yellow Monkey.
Former Arbitrators 
David Gerard, Fred Bauder, Jayjg, Mackensen*, Raul654, Rebecca*, Sam Korn, The Epopt.
Brion VIBBER, Tim Starling, Voice of All.
Alison, Cary Bass, Hei ber*, Lar, Redux, Thatcher, Wikimedia staff members

Developers do not typically patrol the site for violations, but require occasional access for maintenance and enhancement purposes. Members of the Ombudsman commission also do not typically run routine requests for checkuser. "Others" includes non-Arbitrators selected for the permission, and WMF officers.

*: denotes members of the Ombudsman commission, who have global CheckUser access; see also Special:GlobalUsers/Ombudsmen.

See also[cancia]

CheckUser access
Related pages
  • mw:CheckUser; more detailed description of how the feature works and how to install the extension on one's own wiki.