When evaluating the quality of the information you are using, it is useful to identify whether you are using a Primary, Secondary, or Tertiary source. By doing so, you will be able to recognize whether 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 the primary source. It leads the researcher to a secondary source, rather than to the primary source. |
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| Discipline | Primary | Secondary |
| Literature | Poem | Scholarly article interpreting poem |
| Theology (example) | Institutes of the Christian Religion--John Calvin | A Theological Guide to Calvin's Institutes |
| Theology (example) | The Collected Letters of C. S. Lewis | C. S. Lewis: A Biography |