This is an essay on the Wikipedia is not a directory policy.
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.
Listcruft is a term some editors use to refer to indiscriminate or trivial lists. The term derives from the older hacker term cruft, describing obsolete code that accumulates in a program. The term is a neologism largely restricted to Wikipedia and its mirrors; as such, it is inappropriate for use in the text of articles (per Wikipedia:Avoid neologisms and Wikipedia:Avoid self-references), although it is freely used in certain article tags and on article talk pages.
In general, a "List of X" stand-alone list article should only be created if X itself is a legitimate encyclopedic topic that already has its own article. The list should originate as a section within that article, and should not be broken out into a separate article until it becomes so long as to be disproportionate to the rest of the article. It is very appropriate for the article on Zoology to include a list of important zoologists within it, and for the article on the fictional series character Rick Brant to include a list of the Rick Brant books.
In particular, if X is an encyclopedic topic, the X page should not consist only of a "list of X", in effect ostensively defining the topic. Effort should be made to write an article which verifiably defines and characterizes the topic first.
Valid examples of standalone lists would include List of University of Chicago people and List of Oz books. In both cases, the lists correspond closely to encyclopedia articles—University of Chicago and L. Frank Baum, respectively—and in both cases the length and detail of the list justify breaking them out.
On the other hand, topics such as List of small-bust models and performers, List of songs that contain the laughter of children, and List of nasal singers should be considered highly questionable because there are no articles on those topics.
If a Wikipedia editor refers to a list as listcruft, it generally indicates they believe the list would not be expected to be included in an encyclopedia. More specifically, an editor's use of the term listcruft generally indicates they are asserting that one or more of the following are true:
- The list is of interest to a very limited number of people
- The list is a violation of Wikipedia is not an indiscriminate collection of information
- The content is unverifiable: the underlying concept is non-notable or poorly defined
- The list cannot be expanded beyond a handful of terms
- The list is unlimited and/or unmaintainable
- The list has no content beyond links to other articles, so would be better implemented as a (self-maintaining) category
- Determining membership of the list requires adoption of a non-neutral point of view, and reliable sources for avoiding it are not available.
- Determining membership of the list involves original research or synthesis of ideas.
- The list's membership is volatile and requires a disproportionate amount of effort to keep up to date.
- The list attracts the addition of little that is of clear importance or even relevance in the context of the topic.
Generally speaking, the perception that an article is listcruft can be a contributing factor to someone voting for deletion, but it might not be the sole factor. In such cases, this perception is generally challenged by those voting for retention.