Sources
editReliable sources
editAny material that is challenged or likely to be challenged must be accompanied by a reliable source. Material that counts as "original research" within the meaning of this policy is material for which no reliable source can be found and which is therefore believed to be the original thought of the Wikipedian who added it. The only way to show that your work is not original research is to produce a reliable published source that advances the same claims or makes the same argument as you.
In general, the most reliable sources are books, journals, magazines, and mainstream newspapers; published by university presses or known publishing houses. As a rule of thumb, the more people engaged in checking facts, analyzing legal issues, and scrutinizing the writing, the more reliable the publication. Material that is self-published, whether on paper or online, is generally not regarded as reliable, but see Wikipedia:Verifiability for exceptions.
Primary, secondary, and tertiary sources
editResearch that consists of collecting and organizing material from existing sources within the provisions of this and other content policies is encouraged: this is "source-based research," and it is fundamental to writing an encyclopedia. However, care should be taken not to "go beyond" the sources or use them in novel ways. Sources may be divided into three categories:
- Primary sources are documents or people very close to the situation being written about.. Primary sources that have been published by a reliable source may be used in Wikipedia, but only with care, because it is easy to misuse them. For that reason, anyone—without specialist knowledge—who reads the primary source should be able to verify that the Wikipedia passage agrees with the primary source. Any interpretation of primary source material requires a secondary source. Examples of primary sources include archeological artifacts; photographs; historical documents such as diaries, census results, video or transcripts of surveillance, public hearings, trials, or interviews; tabulated results of surveys or questionnaires; written or recorded notes of laboratory and field experiments or observations; and artistic and fictional works such as poems, scripts, screenplays, novels, motion pictures, videos, and television programs.
An article or section of an article that relies on a primary source should (1) only make descriptive claims, the accuracy of which is easily verifiable by any reasonable, educated person without specialist knowledge, and (2) make no analytic, synthetic, interpretive, explanatory, or evaluative claims. Contributors drawing on primary sources should be careful to comply with both conditions.
- Secondary sources draw on primary sources to make generalizations or interpretive, analytical, or synthetic claims. A journalist's story about a traffic accident or a Security Council resolution is a secondary source, assuming the journalist was not personally involved in either. An historian's interpretation of the decline of the Roman Empire, or analysis of the historical Jesus, is a secondary source.
- Tertiary sources are publications such as encyclopedias and other compendia that sum up other secondary sources and primary sources. Some tertiary sources are more reliable than others, and within any given tertiary source, some articles may be more reliable than others. For example, articles signed by experts in a general or specialized encyclopedia can be regarded as reliable sources.
Secondary and tertiary sources should be used in a way that does not give rise to new analysies, syntheses or original conclusions that are not already present in the sources. In short, the policy of "No original research" requres that wikipedia users stick to the sources.