What are Primary and Secondary Sources?
Brought to you by the University of Houston Libraries.

Sometimes during the course of your research, your instructor may ask you to use primary sources. But what is a primary source, and what distinguishes it from a secondary source?

A primary source is a firsthand account of a topic, generally created by someone who had direct knowledge of the event or topic described, and created during the time period being studied.

Examples of primary sources include research studies, statistics, data, diaries, letters, interviews, art, maps, videos, legal documents, government documents, and even a Tweet or other form of social media.

Secondary sources analyze, interpret, and synthesize primary sources.

Examples include books, and scholarly and magazine articles that interpret or analyze previous findings.

However, it’s important to keep in mind that whether a source is a primary or secondary source will depend on the context in which it’s used, and primary and secondary sources are different depending on the discipline or subject area.

For example, original, scholarly research articles are considered primary sources in the sciences and social sciences, but are generally considered secondary sources in the humanities.

Let’s say you’re conducting historical research about the incarceration of Japanese Americans during World War II, and in the library you find a collection of letters from the 1940s written by a family who lived in the internment camps.

Those letters would be considered a primary source because they offer first hand accounts of the event you are studying, written by people with direct knowledge of the event.

Later you find a scholarly book on the topic of Japanese American internment written by a researcher from the 1990s. It is considered a secondary source, because it does not come from the time period you’re researching and does not offer first hand evidence of the event.

Instead, it synthesizes and interprets various primary sources about the event to make its argument.

Now let’s say you’re writing a research paper for your health sciences class about the human immune system and you find several scholarly articles describing original research about new treatments for autoimmune disorders.

Those would be considered primary sources because they provide a full description of original research and were written by scholars with direct knowledge of the topic.

You also find a textbook about the human immune system that provides a comprehensive overview of the subject. That’s considered a secondary source because it synthesizes and analyzes previous research findings.

If you still have questions about primary and secondary sources, contact UH Libraries for help.