Selecting Sources: Tertiary, Secondary, Primary


When conducting research, you will likely use three types of sources: primary, secondary, and tertiary. While exact definitions may vary by discipline or institution, we hope this post will help you sort out the main distinctions between these types of sources and when to use each in the research process for National History Day (NHD) and other research projects. When creating NHD or other research projects, you will use secondary and primary sources and, possibly, tertiary sources but your completed project typically be considered a secondary source.


Tertiary sources give a broad view of topics by compiling and synthesizing information from secondary and primary sources, often listing, summarizing, or repacking ideas or information found elsewhere.


  • abstracts
  • bibliographies
  • chronologies
  • classifications
  • dictionaries
  • directories
  • encyclopedias (considered secondary sources by NHD)
  • indices
  • textbooks (may also be considered secondary sources)

Research uses

  • Provide an overview of a topic, often highlighting background information and possible issues related to a certain topic.
  • Useful to help narrow a topic and discover secondary and primary sources to use in further research.
  • Are generally not cited in a final research project.

Secondary sources are accounts of events or people created after the time under study with the benefit of hindsight. They discuss, analyze, evaluate and interpret primary source evidence as well as comparing and contrasting a particular point of view with those provided by other secondary sources. They cite and may also include the primary sources they reference. Determining if a source is secondary also depends a lot on how or why it is being used in your research, but the sources listed below are generally considered to be secondary.


  • articles—journal, magazine, newspaper (also considered primary in some cases, including articles authored by a person being researched, eye-witness accounts, and editorials)
  • biographies and other non-fiction books
  • commentaries, criticisms, or analyses
  • documentaries
  • encyclopedias (secondary for NHD but usually considered tertiary sources)
  • websites (may also be considered primary sources)

When a secondary source becomes primary

News articles are generally considered secondary sources so when might they be considered primary sources instead?

  • If you are studying how a particular event was covered by different news organizations or how various media characterized a person.
  • If you are studying how the media remembered a historical event or person.
  • If you are studying the type, style and format of media coverage of a certain time period.

For more examples, check out this list describing various sources from Yale University.

Research uses

  • Useful to examine different perspectives and interpretations of events, people, and issues.
  • Provide deeper background knowledge and historical context.
  • Help narrow research focus and locate related primary sources.
  • Model the construction of a historical argument.
  • Must be cited in a final research project.

For information, review this great resource on locating and “reading” secondary resources from Chicago Metro History Education Center (CMHEC) .


The Library of Congress describes primary sources as “the raw materials of history”. They are original objects, documents and other works created at or near the time under study. They include records of events and personal recollections and interpretations of by those who experienced them. Primary sources are characterized by their content and not their format (i.e., a digital image of a document is just as valid as reviewing the physical document).


  • artifacts (e.g., coins, clothing, furniture, tools)
  • audio recordings (e.g., song recordings, radio programs, oral histories)
  • autobiographies
  • correspondence (letters, telegrams, e-mails)
  • diaries or personal journals
  • interviews and personal narratives
  • maps and charts
  • official documents (e.g., birth certificate, marriage license, trial transcript, will)
  • photographs
  • printed ephemera (e.g., broadsides, posters, ticket stubs, receipts)
  • organizational and government records (e.g. annual reports, treaties, legislation)
  • sheet music or song sheets
  • speeches
  • video recordings
  • works of art, architecture, literature, and music (e.g., paintings, sculptures, buildings, novels, poems, sheet music, song sheets)

Research uses

  • Useful to examine different perspectives and interpretations of events, people, and issues.
  • Serve as focal points of discussion and illustrate text.
  • Provide evidence for theories and to back up claims.
  • Must be cited in a final research project.
Related resources

Selecting Primary Sources for Research Projects

Using Sources: Citing Digitized Sources from the Library

Using Sources: Creating a Digital Annotated Bibliography