What Is Information Literacy?
Primary vs. Secondary Sources
Not all sources are created equal — and not all sources serve the same purpose. One of the most important distinctions in research is between primary and secondary sources. Understanding the difference helps you choose the right source for the right question.
What Is a Primary Source?
A primary source is original, firsthand evidence created at the time of an event or by someone directly involved. It has not been filtered, interpreted, or analyzed by another person.
- Diaries, letters, and personal journals
- Original research studies and scientific data
- Photographs, audio recordings, and video footage
- Government documents, laws, and court decisions
- Speeches, interviews, and oral histories
- Works of art, literature, and music
What Is a Secondary Source?
A secondary source analyzes, interprets, or summarizes primary sources. It is one step removed from the original event or data.
- Textbooks and encyclopedias
- Biographies and historical analyses
- News articles reporting on events
- Review articles summarizing research
- Documentaries and podcasts about historical events
The same source can be primary or secondary depending on your research question. A newspaper article from 1945 is a secondary source if you are studying World War II events — but it is a primary source if you are studying how journalists wrote about the war at the time.
Tertiary Sources
Tertiary sources compile and summarize secondary sources. Indexes, abstracts, databases, and Wikipedia are tertiary sources. They are useful for getting an overview or finding primary and secondary sources — but they are rarely appropriate to cite in academic work.
When to Use Each Type
- Use primary sources when you need original evidence, firsthand accounts, or raw data
- Use secondary sources when you need analysis, context, or expert interpretation
- Use tertiary sources to orient yourself and find better sources — not as final citations
Primary vs. Secondary Sources · What Is Information Literacy?
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