Wikipedia:Verifiability

In the English Wikipedia, verifiability means other people using the encyclopedia can check that the information comes from a reliable source. Its content is determined by previously published information rather than editors' beliefs, opinions, experiences, or previously unpublished ideas or information. Even if you are sure something is true, it must have been previously published in a reliable source before you can add it.^[a] If reliable sources disagree with each other, then maintain a neutral point of view and present what the various sources say, giving each side its due weight.

"WP:V" redirects here. For discussing particular sources, see Wikipedia:Reliable sources/Noticeboard. For vandalism, see Wikipedia:Vandalism.