Source Types
Sources can be classified into different types, each serving a distinct purpose depending on the nature of the information and its relevance to your topic. Knowing how information evolves is important for determining the usability of a source.
Primary, Secondary, and Tertiary Sources
Different fields use the term "primary source" to mean different things, so make sure you consult the appropriate definition for your subject area.
- Primary Sources
- In the humanities and social sciences such as history, education, art, political science, religion, literature, and related fields, a primary source is evidence that was produced at the time of an event.
Examples include: photographs, letters, speeches, oral histories, or political documents.
- In the sciences and some social science contexts including chemistry, biology, environmental studies, and psychology, a primary source is original scientific research often produced through lab experiments or field work.
- Secondary Sources
- A secondary source is an analysis of the observations or data found in primary sources, and often examines those original sources in the context of broader backgrounds, themes, and trends.
Examples include: reviews, criticism, reports, histories, commentaries, and summaries.
- Tertiary Sources
- Tertiary sources summarize the content of primary and secondary sources, and are often used for background reading, fact checking, and research preparation.
Examples include: encyclopedias, bibliographies, dictionaries, indexes, and Wikipedia.
This content is adapted from "Introduction to Primary Sources" by the University of Massachusetts Global and has been made available through a CC BY-SA 4.0 License.
Peer-Reviewed Academic Journal Articles
Peer-review is a process that helps establish trust in academic, scholarly publications. The peer review process is intended to work as a quality check on articles that have been submitted to a specific journal for publication. When authors submit an article to a journal that uses a peer review process, a group of experts in the field will review the work and verify that it is of high quality before it is published. The process often occurs in cycles, with authors revising their work multiple times based on feedback from the reviewers before their article is eventually published by the journal.
For more information on peer-review and how it differs from other models of academic publishing, see the library's Peer-Review vs. Preprints guide.