Primary, Secondary and Tertiary Sources

  • Context determines whether a source is primary, secondary or tertiary. Sources that are normally considered to fit into one category may sometimes be used as another. For example, a magazine article reporting on recent studies linking the rise in popularity of low emission vehicles such as the Prius, Volt, and Leaf, to an overall improvement in air quality worldwide would be a secondary source.
  • A research article or study proving this would be a primary source.
  • However, if you were studying how low emission vehicles are presented in the popular media, the magazine article could be considered a primary source.

Each content area, and sometimes individual teachers, has its own set of standards for what counts as a primary source; when in doubt, ask your teacher.

What they are and why it matters

Primary sources

Primary sources are original materials on which other research is based. They are usually the unique examples of results in physical, print or electronic format. They present original thinking, report a discovery, or share new information.
Note: The definition of a primary source may vary depending upon the discipline or context.

  • Novels, plays, poems, works of art, popular culturediaries, narratives, autobiographies, memoirs, speeches
  • Government documents, patents
  • Data sets, technical reports, experimental research results
  • Artifacts (e.g. coins, plant specimens, fossils, furniture, tools, clothing, all from the time being studied);
  • Audio recordings (e.g. radio programs and podcasts)
  • Internet communications on email, listservs;
  • Interviews (e.g., oral histories, telephone, e-mail);
  • Journal articles published in peer-reviewed publications;
  • Letters;
  • Newspaper articles written at the time;
  • Original Documents (i.e. birth certificate, will, marriage license, trial transcript);
  • Patents;
  • Photographs
  • Proceedings of Meetings, conferences and symposia;
  • Records of organizations, government agencies (e.g. annual report, treaty, constitution, government document);
  • Speeches;
  • Survey Research (e.g., market surveys, public opinion polls);
  • Video recordings (e.g. television programs, vlogs);
  • Works of art, architecture, literature, and music (e.g., paintings, sculptures, musical scores, buildings, novels, poems).
  • Web sites (but only if the site meets the criteria listed above.  Wikipedia, for example, is a website but it is not a primary source).
Secondary sources

Secondary sources analyze, review or restate information in primary resources or other secondary resources. Even sources presenting facts or descriptions about events are secondary unless they are based on direct participation or observation. Moreover, secondary sources often rely on other secondary sources and standard disciplinary methods to reach results, and they provide the principle sources of analysis about primary sources. Examples include:

  • Biographies
  • Review articles and literature reviews
  • Scholarly articles that don't present new experimental research results
  • Historical studies
  • Research papers 
Tertiary sources

Tertiary resources provide overviews of topics by synthesizing information gathered from other resources. Tertiary resources often provide data in a convenient form or provide information with context by which to interpret it. Examples include:

  • Encyclopedias
  • Chronologies
  • Almanacs
  • Textbooks

The information above was excerpted from the following websites: