View source for Wikipedia:No original research

=== Reliable sources ===
{{See|Wikipedia:Verifiability|Wikipedia:Identifying reliable sources}}
Any material that is challenged or [[WP:LIKELY|likely to be challenged]] must be supported by a reliable source. Material for which no reliable source can be found is considered original research. The only way you can show your edit is not original research is to cite a reliable published source that contains the same material. Even with well-sourced material, if you use it out of context, or to reach or imply a conclusion not {{em|directly and explicitly}} supported by the source, you are engaging in original research; see [[WP:SYN|below]].

In general, the most reliable sources are:
* Peer-reviewed journals
* Books published by university presses
* University-level textbooks
* Magazines, journals, and books published by respected publishing houses
* Mainstream newspapers

As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication. Self-published material, whether on paper or online, is generally not regarded as reliable, but see [[WP:SPS|self-published sources]] for exceptions.

Information in an article must be [[Wikipedia:Verifiability|verifiable]] in the references cited. In general, article statements should not rely on unclear or inconsistent passages, or on passing comments. Passages open to multiple interpretations should be precisely cited or avoided. A summary of extensive discussion should reflect the conclusions of the source. Drawing conclusions not evident in the reference is original research regardless of the type of source. It is important that references be cited in context and on topic.