 | This is an essay on Wikipedia categorization. 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. |
 | This page in a nutshell: Don't remove all/most items from a category (before/after nominating it for discussion). This may violate WP:CFD policy, and hinder the community in assessing the category's purpose and whether/how its items are related. Improper ECOOPing is sanctionable as disruptive editing. |
Users – editors, admins, and bots – should not be emptying categories out of process (ECOOP). That is, remove all/most items from a category before nominating it, or after it has (by that user or another user) been nominated for discussion (deletion, merging, renaming, or splitting). Doing so may constitute a violation of WP:CFD policy, and make it harder for the community to assess the purpose the category may serve, or have served, or could possibly be re-purposed to serve, as well as whether/how its items are related to each other.
Improper emptying (depopulating) of categories shortly before or after nominating them (in order to enable their deletion per this provision) is known as emptying out of process. Cases where a category could get or has been deleted due to having been emptied out of process are known as out of process deletions. There is a rough general agreement that this should not be done, but it is not always clear what exactly constitutes "emptying out of process", and in which cases such conduct should be sanctioned (and how) or not.
Sometimes emptying categories out of process is a sincere mistake anyone can make, and a warning and explanation is enough. In some cases, however, editors knowingly inappropriately empty categories out of process without disclosing this, which is considered disruptive. Such inappropriate ECOOPing may be sanctioned per Wikipedia:Disruptive editing with temporary blocks lasting for several days, indefinite topicbans, and even indefinite blocks (see #Sanction precedents).