Primary, secondary, and tertiary materials
editMost succinctly,
- primary materials are sources of facts
- secondary materials are sources for distinct views of facts, and summaries (or generalizations) of diverse views of facts
More specifically:
- Primary materials include archeological artifacts; photographs; historical documents such as diaries, census results, video or transcripts of surveillance, public hearings, trials, or interviews; tabulated results of surveys or questionnaires;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.
Our policy: A Wikipedia article or section of an article can employ primary materials only if the material is used (1) only to make descriptive claims, the accuracy of which is easily verifiable by any reasonable, educated person without specialist knowledge, and (2) never to make analytic, synthetic, interpretive, explanatory, or evaluative claims. Contributors drawing on primary materials should be careful to comply with both conditions.
- Secondary materials rely on primary materials to make analytic, synthetic, interpretive, explanatory, or evaluative claims. Some secondary materials, for example many scientific publications, often include original data and are thus also primary materials. Some secondary references draw on other secondary materials to provide a comprehensive account of a topic.
Our policy: Wikipedia articles can include analytic, synthetic, interpretive, explanatory, or evaluative claims (1) only if such claims come from a reliable, verifiable source and (2) the point of view is clearly identified and accurately represented. The conditions that apply to the use of primary materials also applies to the use of primary source material included in secondary sources.
Wikipedia does not want to be derivative or duplicate other encyclopedias. All encyclopedias do not necessarily have the same content policies as Wikipedia and therefore should not be viewed as authoritative, though they often contain extensive bibliographies that may be of use for research purposes. However, some encyclopedias have signed articles that often explicitly promote the author's own views. In this sense, such articles may be treated like other secondary materials.