Primary, secondary, and tertiary sources​

​The information below is drawn, in part, from "Evaluating Print Sources" from the Writing Center at UNC-Chapel Hill.
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What is the difference between a primary, secondary, and tertiary source?

  • ​A primary source was produced at the same time that the events described in the source took place. These are the closest you will get to the events "as they happened" but also need to be handled carefully to account for the perspective of the author.
    • An example of a primary source is Franklin D. Roosevelt’s War Message to Congress, 8 December 1941.
  • A secondary source is written later, often based on research incorporating those primary sources. The best secondary sources will be scholarly works produced by historians trained in the process of carefully weighing primary sources and who are intimately familiar with the historical context and the work of other historians.
    • An example of a secondary source is Warren F. Kimball, “Franklin D. Roosevelt and World War II,” Presidential Studies Quarterly, Vol. 34, No. 1, Going to War (Mar., 2004), 83-99. (located via JSTOR search).
  • Tertiary sources are reference materials like encyclopedia that summarize information contained in secondary sources. Tertiary sources are important and you should rest assured that searching on Wikipedia is a good habit. However, it is important to remember that the role of tertiary sources is to provide you with a basic reference rather than in-depth treatment, that the information can be far removed from the original source, and that you should avoid relying too heavily upon—and citing--these in your essays.
    • An example of a tertiary source is “Roosevelt, Franklin D. (1882–1945)” from Propaganda and Mass Persuasion: A Historical Encyclopedia, 1500 to the Present (located via Credo Reference search).

That seems simple enough. When might it get confusing?

  • Diaries and letters written by people who were participants in the actions they describe are easy to classify as primary sources, but what about memoirs or autobiographies? These are usually written well after the events took place and often will tell you more about the period in which they were written than about the period they describe.
  • ​What about newspapers? The author of an article presents an interpretation, but if the article reports current events, it is primary. If the article reports past events, it is secondary. Keep in mind that an article about a past event can present valuable primary evidence concerning the author’s context.