What does primary vs. secondary vs. tertiary mean?
The distinction between primary, secondary and tertiary sources hinges on how far from the original event or phenomenon the information source is created. Is it first-hand knowledge? A second-hand interpretation? A third-hand synthesis and summary of what is known?
Why is this important? Because different kinds of research call for using primary, secondary, and tertiary sources in different ways. For example, a research paper usually requires a combination of primary and secondary sources.
Topic: Performance of a Company
Example of an Appropriate Primary Source: Annual Reports; SEC Filings
Topic: Sinking of a ship in 1920
Example of an Appropriate Primary Source: Newspapers and newsreels about the event; a diary
Topic: Effect of a new medicine on a virus
Example of an Appropriate Primary Source: Data from an experiment
In the sciences, peer-reviewed research articles are considered primary sources because they are full of direct evidence in the form of data. Try searching a science database for articles containing original research and experiments.
Newspapers are key primary sources for past current events. Try searching newspaper databases.
Museums, archives, historical societies, libraries with special collections, and cultural institutions collect pictures, letters, diaries, archival materials, ephemera, etc. Many collections are now available online. Try searching:
If you need statistics and datasets, try: