What is the difference between a primary source and a secondary source?

I. Primary Sources 

original documents or artifacts created during the time period being studied. They often include first-hand or eyewitness accounts or have an inside view of a particular event.

In the sciences, primary sources are usually articles describing research studies that are written by the people who performed the study. See our FAQ on empirical research for more details.

In other disciplines, primary sources might include advertisements, artwork, autobiographies, diaries, field notes, government documents (bills, laws, congressional hearings, etc.), interviews, letters, literary texts, newspaper articles, official records, oral histories, photographs, posters, raw research data, speeches, etc.

Specific examples:

  • Susan B. Anthony's diaries

  • Film footage of the assassination of President J. F. Kennedy

  • The Declaration of Independence (Image from: www.archives.gov)


II. Secondary Sources

interpret or analyze primary sources. They are created after the phenomena they discuss.


  • many scholarly journal articles

    • literature reviews (papers that provide an overview and analysis of other studies)

    • criticism and interpretation

    • historical analysis

  • biographies

  • political commentary analyzing an election or politician

III. Tertiary Sources

provide overviews of a topic and synthesize information from other primary and secondary sources. Examples include textbooks, encyclopedia articles, and Wikipedia.

Expert Advice

Distinguishing between these three types of sources will vary according to context and situation. For example, if you are analyzing how African American history was depicted in middle school textbooks in the 1980s, then the textbooks would be considered a primary source rather than a tertiary source. If you are unsure about a source, check with your instructor or ask the library.