BIOL 201: Tools for Research

Sources of information are considered primary, secondary, or tertiary depending on their originality (who did the original work; does it comment on other works) and their proximity (is this a first-hand account, or after the fact). While reviewing literature for a paper or project, you will want to consider whether the literature is a primary, secondary, or tertiary source.

It is not always easy to distinguish between the three types of sources, and they even differ between subjects and disciplines (particularly between the sciences and humanities). By understanding the unique characteristics and features of each, you will be able to identify them and maximize their potential use.

Source:  http://libguides.willamette.edu/content.php?pid=105642

Source:  http://libguides.mnu.edu/content.php?pid=296924&sid=2437844

Primary Sources are original materials from the time period involved, and have not been filtered, influenced or analyzed through interpretation. They bring us as close to the original event or thought as possible.

Primary sources consist of works that are the closest to original thoughts or first-hand accounts of events.  Primary sources rarely evaluate or analyze events or information, they simply seek to document it.  Primary resources are normally the first published accounts of an idea, event, or research project.  Essentially, these sources share new information.

General examples of primary resources would be:

• Autobiographies
• Correspondence
• Diaries
• Fiction
• First-hand written and oral accounts of an event
• Historical artifacts 
• Letters
• Newspaper articles written at the time of an event
• Original research
• Peer-reviewed journal articles
• Pictorial works
• Poetry
• Preprints
• Sacred texts in their original languages
• Video recordings
• Works of art, architecture, literature, and music

NOTE:  In the sciences, primary sources include articles that describe original research. 

Secondary Sources build on the primary sources with more extensive and in-depth analyses. They summarize, evaluate, and analytically interpret primary material, often by offering a personal perspective. While these are useful to check what other experts in the field have to say, they are not evidence. It is one step removed from the original source.
General examples of secondary sources would be:

• Accounts of events written a substantial time after the event has occurred
• Analyses
• Biblical commentaries and criticisms
• Biographies
• Biographies (not autobiographies)
• Commentaries
• Dissertations
• Historical studies
• Journal articles that critique the work of others rather than present original ideas
• Literary critiques
• Literature reviews
• Magazine articles
• Monographs (books)
• Public opinion
• Review articles
• Theses

Tertiary Sources are distillations and collections of primary and secondary sources. The information is compiled and digested into factual representation, so that it does not obviously reflect points of view, critiques or persuasions. Tertiary sources are typically the last to be published in the information cycle.

General examples of secondary sources would be:

• Dictionaries
• Directories
• Encyclopedias
• Guides
• Handbooks
• Textbooks
• Websites of general interest
• Wikipedia