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Types of Sources - What's the Difference

Learn quick and easy criteria for differentiating between common source types often used for projects and research at the university.

Primary, Secondary, & Tertiary Sources

Primary Sources are items or original works that are a firsthand record of a topic. What is considered a primary source differs across different disciplines. 

The following are a list of examples of primary sources in various disciplines:

  • Anthropology, Archaeology: Ethnographies, surveys, articles describing research, cultural and historical artifacts
  • Communications, Journalism: News (printed, radio, TV, online), photographs, blogs, social media sites
  • Education, Political Science, Public Policy: Government publications, laws, court cases, speeches, test results, interviews, polls, surveys
  • Fine Arts: Original art work, photographs, recordings of performances and music, scripts (film, theatre, television), music scores interviews, memoirs, diaries, letters, autobiographies
  • History: Government publications, newspapers, photographs, diaries, letters, manuscripts, business records, court cases, videos, polls, census data, speeches, autobiographies
  • Language and Literature: Novels (fiction), plays, short stories poems, autobiographies
  • Psychology, Sociology, Economics: Articles describing research results of experiments, ethnographies, interviews, surveys, data sets
  • Sciences: Articles describing research and methodologies, documentation of lab research, research studies

Content used with permission and adapted from Cubbage, Charlotte. 2017. “Primary Sources.” Primary Sources/Secondary Sources. September 13. http://libguides.northwestern.edu/c.php?g=98366&p=636900.

Secondary Sources are items that interpret, critique, or analyze information, content, or findings of primary sources about a specific topic. These items differ across various disciplines. 

The following are a list of examples of secondary sources in various disciplines:

  • Anthropology, Archaeology: Reviews of the literature, critical interpretations of scholarly studies
  • Communications, Journalism: Interpretive journal articles, books, and blogs about the communications industry
  • Education, Political Science, Public Policy: Reviews of the literature, critical interpretations of scholarly studies
  • Fine Arts: Critical interpretations of art and artists (all formats), biographies, reviews, textbooks
  • History: Interpretations in any format such as journal articles, books, multimedia, websites
  • Language and Literature: Literary criticism, biographies, reviews, textbooks, language manuals
  • Psychology, Sociology, Economics: Reviews of the literature, critical interpretations of scholarly studies
  • Sciences: Publications that review or discuss the significance of research or experiments

Content used with permission and adapted from Cubbage, Charlotte. 2017. “Primary Sources.” Primary Sources/Secondary Sources. September 13. http://libguides.northwestern.edu/c.php?g=98366&p=636900.

Tertiary Sources are items that compile information from secondary and primary sources to provide a broad overview of the representation of a topic or related topics. These items have the most commonality across disciplines. 

The following are a list of examples of tertiary sources in various disciplines:

  • Anthropology, Archaeology: Encyclopedias, dictionaries, bibliographies, handbooks
  • Communications, Journalism: Encyclopedias, dictionaries, bibliographies, handbooks
  • Education, Political Science, Public Policy: Encyclopedias, dictionaries, bibliographies, graphical representation of data (i.e. data visualization)
  • Fine Arts: Guides, dictionaries, bibliographies, discographies
  • History: Encyclopedias, dictionaries, bibliographies, indexes
  • Language and Literature: Bibliographies, compilations, indexes, dictionaries
  • Psychology, Sociology, Economics: Handbooks, manuals, encyclopedias, dictionaries
  • Sciences: Dictionaries, manuals, handbooks, bibliographies