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Primary, Secondary and Tertiary Sources

Definitions and examples of primary, secondary and tertiary sources

Primary Sources

Primary sources provide first-hand observations or direct evidence concerning a topic under investigation. They are created by witnesses or recorders at or near the time of the event. They have not been filtered through further interpretation or evaluation. 

Some examples of primary sources are:

  • diaries and letters
  • academic articles reporting NEW data and findings - these are often peer reviewed and called empirical research
  • works of literature (poems, novels, etc.)
  • works of fine art (paintings, sculpture, pottery, etc.)
  • works of performance art (music, fictional films, plays, musicals, operas, etc.
  • official records from a government, judicial court, or company
  • maps
  • oral histories
  • speeches
  • autobiographies
  • eyewitness new reports*

*Newspaper articles that report on a recent event can be primary sources, but articles that rehash previous events are not primary sources, unless they add new information to the story.

Where do I find primary sources?

It depends on your discipline, but here are are some places to start.

  • Academic journals are the main place that most researchers will initially publish the results of their research and/or experiments, though some disciplines will favor book length publications.
  • Creative works like novels, films, music, and other works of art can often be found through the library catalog or special databases from that discipline.
  • Historical sources like newspapers, diaries, letters, oral histories, and more can be found through archival collections, like the Lear-Carson Collection and the many online archival databases to which the library subscribes.
  • The library's homepage search box or subject specific databases are great places to start searching!

Secondary Sources

Secondary sources offer an analysis or a restatement of an event or discovery described in primary sources. They interpret, explain, critique, or otherwise analyze primary sources. Some secondary sources are used to persuade the reader and may be considered less objective. 

Examples of secondary sources include:

  • criticism of a work of art, music, or fiction
  • publications that discuss or analyze a topic
  • articles and editorials that interpret or review research works or other primary sources*
  • some nonfiction books written for general public for entertainment purposes rather than scholarship
  • some textbooks

Where do I find secondary sources?

It depends on your discipline, but here are are some places to start.

Tertiary Sources

Tertiary Sources offer a summary or restatement of facts and research from both primary and secondary sources. The main difference between secondary and tertiary sources is that tertiary sources offer no new information and no analysis of the information from primary and secondary sources.

Tertiary sources may include

  • Reference Works: encyclopedias, abstracts
  • Lists or Collections: bibliographies, finding aids
  • Search Tools: library database or catalog, indexes
  • Some textbooks

Where do I find tertiary sources?

The following databases contain reference sources like encyclopedia, dictionaries, and handbooks.

Gale Ebooks - A database of encyclopedias and reference sources. For multidisciplinary research.

History Reference Center - Features full text for more than 1,990 reference books, encyclopedias and non-fiction books from leading history publishers

Oxford Reference - A collection of digitized titles from the Oxford University Press collection of scholarly Dictionaries, Companions and Encyclopedias.

Sage Reference - Hundreds of authoritative encyclopedias and handbooks in the social and behavioral sciences.


Primary Secondary Tertiary
The text of The Gettysburg Address An analysis of The Gettysburg Address A U.S. history textbook
Census data for New York City A book about demographic changes in New York City A chronology of major events in New York City
A Nike commercial A documentary about Nike advertising An encyclopedia of major marketing campaigns
The results of an experiment or clinical trial An article citing different treatments options A medical dictionary
An interview with a Vietnam War veteran A documentary featuring interviews with veterans An anthology of first hand accounts from the Vietnam War