Wikipedia:How the presumption of notability works

The general notability guideline creates a presumption of notability. The presumption (or assumption) is that topics that have significant coverage in independent, reliable sources should have a Wikipedia article written about it. An editor may show that the presumption may not apply to a topic through the deletion process. Other editors then have the burden to show that an article topic is notable.

Reason for the presumption
The presumption of notability exists because the Wikipedia community has reached a consensus that significant coverage in independent, reliable sources usually indicates that a topic is worthy of note and because most things are not inherently notable. However, the presumption is just an assumption or rule of thumb, and so it can be rebutted. That means that any editor can show that it does not apply to a certain topic or that there should not be an article about that topic on Wikipedia. An editor usually shows that a topic is not notable through the deletion process.

The presumption before the deletion process
Before beginning the deletion process, an editor who thinks that an article should be deleted must first show that the presumption does not apply. During a deletion discussion, any editor arguing to keep an article must show that it does. A person advocating for deletion may also show that even if there is significant coverage in reliable sources, an article should not be created on a particular topic if it is inconsistent with Wikipedia's purposes.

An editor is expected to search for sources before proposing (via proposed deletion [PROD]) or nominating (at articles for deletion [AfD]) an article for deletion. A search showing a lack of sources meets will generally meet that burden. Generally, when using PROD or at AfD, an editor must explain that they conducted a search and explain why the sources that they found do not meet the presumption.

The presumption during the deletion process
Once a deletion discussion at AfD is started, an editor arguing to keep an article usually must prove that a topic is notable or show that the argument for deletion is flawed. An editor has that burden because information on Wikipedia, including a claim of notability, must be verified in reliable sources. An editor can usually show that a topic is notable by explaining why there are enough reliable sources with significant coverage to write an article on the topic.

Subject-specific notability guidelines
Some topics have a subject-specific notability guideline (SNG). An SNG gives examples of certain topics that are likely to have significant coverage in reliable sources. For example, the SNG for track-and-field athletes says that any athlete who "[has] a non-relay mark listed on the IAAF senior all-time list or equivalent list" is likely to have significant coverage written about them in independent, reliable sources.

Most editors believe that an article must still meet the GNG even if it is covered by an SNG. Some editors believe that SNGs require a more thorough search before proposing or nominating an article for deletion, and that the burden of production is on an editor advocating for deletion to show that no sources exist, rather than on an editor who would like to keep an article to show that sources exist.