Primary, Secondary & Tertiary Sources

Not quite sure what ‘primary’ sources are, but your professor requires you to use them ? Use of primary resources is preferred or even required in many academic research fields. The definition of a primary source can vary a bit from one discipline to another. For example, a primary source in the sciences differs from a primary source in humanities.

This guide will explain the differences between the kinds of sources you will likely encounter as you begin to research your topic, and will help you to distinguish among them to successfully locate the types of items you need.

This guide is available in pdf format (pdf 44.67 kB)  for printing.

Primary sources are the easiest to define. These include items from the same time period involved; have not been filtered or revised by interpretation; and share new information.

Definitions of primary sources:
 ✓ information in its original form
 ✓ present original thinking
 ✓ first-hand by participants or witnesses

Examples of primary sources:
 ✓ diaries, memoirs
 ✓ autobiographies
 ✓ letters and correspondence
 ✓ government documents, laws, hearings
 ✓ interviews with eyewitnesses or participants
 ✓ works of art and photographs
 ✓ experimental research reports
 ✓ poems, songs, stories or films of the era

Secondary sources are a little more difficult to define. Some secondary sources could be considered as primary or even tertiary sources. A newspaper article is a primary source if the reporter is a witness or interviews witnesses to an event, but secondary if it interprets and comments on the event.

Definitions of secondary sources;
 ✓ interpretation and evaluation of primary sources
 ✓ written after the fact, with benefit of hindsight
 ✓ often biased, persuasive or argumentative
 
Examples of secondary sources:
 ✓ commentaries
 ✓ biographies
 ✓ magazine articles (can be primary)
 ✓ newspaper articles (can be primary)
 ✓ review articles and literature reviews
 ✓ history research books or articles
 ✓ textbooks