Wikipedia:Reliable sources and undue weight

Neutral Point of View says that the article should fairly represent all significant viewpoints that have been published by a verifiable source, and should do so in proportion to the prominence of each. Now an important qualification: Articles that compare views need not give minority views as much or as detailed a description as more popular views, and may not include tiny-minority views at all (by example, the article on the Earth only very briefly refers to the Flat Earth theory, a view of a distinct minority). We should not attempt to represent a dispute as if a view held by a small minority deserved as much attention as a majority view, and views that are held by a tiny minority should not be represented except in articles devoted to those views. To give undue weight to a significant-minority view, or to include a tiny-minority view, might be misleading as to the shape of the dispute. Wikipedia aims to present competing views in proportion to their representation among experts on the subject, or among the concerned parties. This applies not only to article text, but to images, external links, categories, and all other material as well.

Undue weight applies to more than just viewpoints. Just as giving undue weight to a viewpoint is not neutral, so is giving undue weight to other verifiable and sourced statements. An article should not give undue weight to any aspects of the subject, but should strive to treat each aspect with a weight appropriate to its significance to the subject. Note that undue weight can be given in several ways, including, but not limited to, depth of detail, quantity of text, prominence of placement, and juxtaposition of statements.

Minority views can receive attention on pages specifically devoted to them—Wikipedia is not paper. But on such pages, though a view may be spelled out in great detail, it should not be represented as the truth.

From Jimbo Wales, paraphrased from this post from September 2003 on the mailing list:
  • If a viewpoint is in the majority, then it should be easy to substantiate it with reference to commonly accepted reference texts;
  • If a viewpoint is held by a significant minority, then it should be easy to name prominent adherents;
  • If a viewpoint is held by an extremely small (or vastly limited) minority, it does not belong in Wikipedia (except perhaps in some ancillary article) regardless of whether it is true or not; and regardless of whether you can prove it or not.

Views held only by a tiny minority of people should not be represented as significant minority views, and perhaps should not be represented at all.

If you are able to prove something that no one or few currently believe, Wikipedia is not the place to premiere such a proof. Once a proof has been presented and discussed elsewhere, however, it may be referenced. See: Wikipedia:Attribution