|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
The scope of an article is the range of detail covered by the topic or article title; it is the essential subject matter. The extent of the subject matter identifies the range of material that belongs in the article, and thus also determines what does not belong (i.e., what is "out of scope"). Agreement about what information or detail belongs in an article is best determined by reference to reliable sources.
The lead, ideally the introductory sentence or at least introductory paragraph, of an article, should make clear what the scope of the article is.
Aim of scope
- All material that is notable, referenced, and that reliable sources on the topic cover when discussing the subject, should be considered for inclusion in the article (at least in a summarised fashion).
- Material that is not mentioned by reliable sources on the topic when discussing the subject, are unlikely to be within the scope of the article. If sword-wielding skeletons are not mentioned by reliable sources when discussing the Peloponnesian War, it would be fair to say they are out of scope.
- What reliable sources say about material that is out of scope for the decided-upon subject is largely irrelevant to that article and can be removed or moved to another article.
Identifying the scope
- Article scope, in terms of what exactly the subject and its scope is, is defined by reference to reliable sources.
- The suitability of Wikipedia having an article on a subject is decided by reference to WP:Inclusion criteria - appropriate topics are those that have gained sufficiently significant attention by the world at large and over a period of time - so they are "notable", and are not disallowed by policy.
- Scope should have little to do with NPOV. NPOV is to do with how much of the article is given over to any given thing, scope is to do with whether it even can be mentioned or summarised or not.
- Artificially or unnecessarily restricting the scope of an article to select a particular POV on a subject area is frowned upon, even if it is the most popular POV.
- When the name of an article is a term that refers to several related topics in secondary reliable sources, primary topic criteria should be followed to determine if any of the uses of that term is the primary topic, and, if so, then the scope of the article should be limited to, or at least primarily, cover that topic. For example Cat is limited in scope to the primary topic for cat, the Domestic cat (which is a redirect to Cat), even though lions and tigers are considered to be "cats" in the broad sense of that term.
- Use the most general scope for each article you can. Since Wikipedia is a general encyclopedia, it's supposed to summarise essentially all knowledge. Hence accidental or deliberate choice of a limited scope for an article can make notable information disappear from the encyclopedia entirely, or make it highly inaccessible. Since the primary purpose of the Wikipedia is to be a useful reference work, narrow article scopes are to be avoided.
- Looking at what scopes other encyclopedias have chosen can often be useful
Editors are advised to stay on topic, and to ensure that articles contain no irrelevant (nor only loosely relevant) information.
When to split
The two main reasons for splitting material out from an article, are size and content relevance. If either the whole article, or the specific material within one section becomes too large, or if the material is seen to be inappropriate for the article due to being out of scope, then a split may be considered or proposed. Consideration must be given to size, notability and potential neutrality issues before proposing or carrying out a split.