Communication Studies Courses: Classifying Sources

When searching for sources, you will likely get a lot of results. However, not all of the sources you find are the same type, and not all of them will be used in your research the same way. 

One way to classify sources is by the source's function and relationship to original ideas and original information. The categories we use for this are Primary sources, Secondary sources, and Tertiary sources. 

Adapted from "File:Sources of information diagram.svg" by Raster graphic Jreferee Derivative vector Jdcollins13 is licensed under CC BY-SA 3.0.

Primary sources represent original work and/or document an event at the time of its occurrence. 

• Photographs
• Letters
• A work of fiction
• A table displaying raw data

Secondary sources are analyses of/responses to primary sources. They can also synthesize several primary sources (and even other secondary sources) in an analytical way. Secondary sources may or may not be peer-reviewed.

• A book review
• An article in a peer-reviewed journal

Tertiary sources are generally summative in nature; they cover the broad ideas, trends, and themes of a given subject without a particularly critical or analytic lens. 

• A dictionary entry 
• an encyclopedia of American History
• Cliff's Notes of Moby Dick

Another way to classify sources is as Scholarly and Popular sources. Both can be used in research, but they cannot be used interchangeably. 

Scholarly sources are written by experts in a given field, are often peer-reviewed by other experts in the same field, and are written with an audience of experts in mind.

• Scholarly sources are great for providing supporting evidence for a claim, explaining an idea, and building on an expert's existing idea.
• Examples include scholarly journals (peer-reviewed journals), and books written by acclaimed experts (with bibliographies/references included).
   

Popular sources are written by a variety of people, but often journalists or professional writers; they are reviewed by general editors (if at all), and are written for a general public audience.

• Popular sources can be used to articulate a point of view from the public, or for providing a real-life example of a phenomenon or event. They are not as useful when supporting a claim or argument, though.
• Examples include magazines, newspapers, some books (especially those without bibliographies or references).

The scholarly - popular distinction exists on a spectrum: a source may have many characteristics that are scholarly, but also have some characteristics indicative of a popular source. 

See the video and handout below for a more detailed explanation.