Primary, Secondary, & Tertiary

Primary source: an original document/image, the results of an experiment, statistical data, first-hand account, or creative work.
Secondary source: something written about or using primary sources.
Tertiary source: a collection of primary and secondary sources.

Examples of Primary, Secondary, and Tertiary Sources
Primary	Secondary	Tertiary
The text of The Gettysburg Address	An analysis of The Gettysburg Address	A U.S. history textbook
Census data for Detroit	A book about demographic changes in Detroit	A chronology of major events in Detroit
A McDonald's commerical	A documentary about McDonald's advertising	An encyclopedia of major marketing campaigns
The results of an experiment or clinical trial	An article citing different treatment options	An medical dictionary
An interview with a World War Two veteran	A documentary featuring interviews with veterans	An anthology of first hand accounts from World War Two

How to Research Guide