When evaluating the quality of the information you are using, it is useful to identify if you are using a Primary, Secondary, or Tertiary source. By doing so, you will be able recognize if the author is reporting on his/her own first hand experiences, or relying on the views of others.
| Source Type | Examples |
| Primary A primary source is a first person account by someone who experienced or witnessed an event. This original document has not been previously published or interpreted by anyone else. |
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| Secondary A secondary source is one step removed from the primary original source. The author is reexamining, interpreting and forming conclusions based on the information that is conveyed in the primary source. |
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| Tertiary A tertiary source is further removed from primary source. It leads the researcher to a secondary source, rather than to the primary source. |
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Sources can be divided into three types, depending on their proximity to the subject of study:
A primary source is usually a document or result that is being reported first hand. In other words, primary sources are original sources, not interpretations made by someone else.
The following often function as primary sources:
Secondary sources value, discuss or comment on the primary source, or on sources analogous to the primary source that is being analysed.
The following are examples of such secondary sources:
A tertiary source is a source that summarises or compiles facts and knowledge produced by someone else. Tertiary sources are often some kind of assemblage of primary and secondary sources. They are convenient for quick access to summarised facts, but not all sources that belong to this category are considered suitable for scholarly writing. For instance, it is usually not acceptable to use compilations of facts instead of reading the original sources. Therefore, students writing essays are recommended to consult their teachers on the suitability of using tertiary sources in their writing.
Sources that would be regarded as tertiary sources include:
It should be noted that the distinction between primary, secondary and tertiary sources is not a fixed one. For instance, in an analysis of an encyclopaedic article, that text would be regarded as a primary source, and in a review of a scholarly monograph, the text under scrutiny would be seen as a primary source, although it would be used as secondary source material under other circumstances.