Primary vs. Secondary Sources

Primary sources

Primary sources provide information directly from an individual who experienced or witnessed the events discussed. The sources must be original to the time period. Examples of primary sources include:

  • Historical documents
  • autobiographies (written by the sources themselves)
  • speeches, interviews, surveys or questionnaires 
  • audio, video or photographical recordings of events
  • letters and diaries 
  • scientific research reports 
  • literary works, films, and art 

Because these sources are primary, you can know that they reflect what the author chose to write at the time, and they give us direct insight into a time period that is past. However, keep in mind that the information in these sources may or may not be accurate and well-reasoned. The Declaration of Independence and Mein Kampf are primary sources, as are any of Thomas Jefferson's notes about the drafting process or any of Adolph Hitler's architectural sketches.

Questions that may help you evaluate your primary sources

  • What was the situation that prompted the writer to compose this document?
  • What was the writer's source of information, motivation for writing, and biases?
  • What other primary sources might expand, clarify, or contradict this document?

Secondary sources

Secondary sources interpret primary sources. These sources provide information indirectly, through authors who have made judgments about the quality of the primary and secondary information they have used. The author did not live through the events but has done research of other sources to collect the information in their work, just like you often do in your own essay writing. Examples of secondary sources include:

  • Most books and reference material 
  • Scholarly articles interpreting data, historical events, or topics about which the author has no personal experience 
  • Documentaries about the past 
  • Critiques of literature, film or art 
  • Biographies 

You must evaluate how well-informed and unbiased the author’s judgments were. A historian's recounting of research on the process of change in government or a psychologist's use of Freudian psychology to analyze Hitler's personality would be examples of secondary sources.

Questions that may help you evaluate your secondary sources

  • What is the writer's expertise in this field?
  • What motivated the writer to compose this document?
  • How is this person evaluated by others who are known to be experts in the field?
  • What is the argument this writer is making about the topic?
  • What contradictions do other sources offer? How credible are they?
  • How is this book or article evaluated by others in the field?
  • Is the information current? Contemporary to the event?

NOTE: The importance of the timeliness of the information for your research will depend on the nature of your research. For some research projects, documents published decades ago would still be of value; in fact, in some cases such material would be essential. If, however, advances are being made on a topic, your information will need to be as current as possible. Keep in mind that if your subject is current, your information should be current.

Condensed from materials prepared by Mary McMullen-Light, Writing Specialist, and Chip Dube, Instructional Support Specialist, Longview Community College, Lee's Summit, Missouri.

Updated June 2022