Skip to Main Content

Primary vs Secondary Sources

Learn the difference between primary and secondary sources.

Primary or Secondary: What's the Difference?

What is a primary source?

Primary sources are produced by participants or direct observers of an event, time period, or research study. These sources may be recorded during the event or later on, by a participant reflecting upon the event. When you are unable to obtain an original source (for example, the signed Declaration of Independence), you will have to rely on copies (photocopies, microfilm, digital copies). Copies, translations, or transcriptions of a primary source still count as a primary source. 

Primary sources exist for all disciplines, including the sciences, social sciences, humanities, and the arts. 


  • Personal materials (letters, diaries, interviews, autobiographies, oral histories, etc.)
  • Original research studies
  • Newspaper articles (depending on the purpose and how they are written)
  • Works of art (novels, plays, paintings, etc.)
  • Images and photographs
  • Original tweets and social media posts
  • Government documents written at the time of the event
  • Legal documents and business/organization records
  • Speeches
  • Data and field notes
  • Public opinion polls

What is a secondary source?

Secondary sources interpret, analyze, or comment on primary sources. They are generally created by people who weren't participants or direct observers of an event, time period, or research study.

It can be difficult to determine whether a source is primary or secondary – and sometimes an item can be both at the same time. Consider the context and content. For example, newspaper articles that are factual, first-hand accounts of an event are primary sources while those that provide interpretation, analysis, or commentary are secondary. Some do both! Newspapers aren't the only type of source that can cause confusion, as shown by the Odlin letter.

Ask a librarian if you have difficulties.

Where can I find these sources?

Both primary and secondary sources can appear in just about any format -- books, journals, websites, original documents, etc. However, sources are rarely identified as primary or secondary within search results. Use the definitions above to help you determine which is which.

If you are looking for historical primary sources, visit our Primary Sources: Where to Find guide.

Ask a librarian for assistance if you are having trouble finding or identifying sources.

Examples by Discipline

Discipline Primary Source Secondary Source
Art Leonardo da Vinci's Mona Lisa. Book exploring themes in Renaissance art.
Biology Polar bear hibernation research study. Literature review comparing hibernation studies.
Business Survey of consumer confidence in Alaska. Blog post discussing the survey results.
Engineering Photograph of 1964 Earthquake damage. Analysis of building design failure in a textbook.
History Trip diary of gold prospector Jane MacDonald. Biography of women gold prospectors.
Literature Toni Morrison's Beloved. Journal article containing a critical analysis of the book.
Psychology Clinical trial on Seasonal Affective Disorder (SAD) treatment. Newspaper article describing the research study.

Primary vs. Secondary Sources Video

Need Help?

Chat, email, call or visit.

Creative Commons License

This work by UAA/APU Consortium Library is licensed under CC BY 4.0. Note that linked content is covered by its own licenses.

We encourage you to license your derivative works under Creative Commons as well to encourage sharing and reuse of educational materials.

Guide Owner

This guide is maintained by Daria O. Carle.