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Citation Glossary

Primary Source

An original document, data, or firsthand account created at the time of an event. Examples include original research, historical documents, and interview transcripts.

Why it matters

Primary sources provide direct evidence for your arguments rather than someone else's interpretation of that evidence. Using primary sources demonstrates critical thinking and original engagement with the material. In many disciplines, over-reliance on secondary sources signals shallow research.

How to use

Identify primary sources relevant to your topic by considering what original evidence exists: lab data, survey results, historical letters, court records, original artworks, or firsthand interviews. Cite them directly rather than relying on another author's summary. When a primary source is hard to access, cite it through a secondary source using proper "as cited in" formatting.

In academic writing

In the sciences, primary sources are original research articles reporting new findings. In history, they are documents from the period being studied, such as diaries, newspapers, or government records. Students writing research papers are typically expected to include a mix of primary and secondary sources, with the balance depending on the discipline and assignment type.

Common mistakes

  • Confusing a review article or textbook with a primary source — these are secondary sources that summarize or analyze original research.
  • Citing a primary source you found mentioned in a secondary source without using the "as cited in" format.
  • Not recognizing that what counts as a primary source varies by discipline — a novel is a primary source in literary studies but not in psychology.

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