Biology: Primary and Secondary Sources

What is Primary and Secondary Literature?

Scientific literature is divided into two basic categories - "primary" and "secondary".

Primary

With primary literature the author (or author group) are performing their own research. They are describing their own research, usually in the form of a journal article. Hallmarks of primary sources are ones that include sections such as an introduction, literature review, methodology, results, discussion, and conclusions, along with a bibliography. Not all primary literature would include all of these sections explicitly named, but these are the most common.

Beware that review articles, where an author is summarizing and synthesizing the work of others, is not considered primary, even if it contains all the sections described above. Review articles are part of the secondary scientific literature.

Secondary

A secondary source interprets and analyzes primary sources. These sources are one or more steps removed from the scientific experiment. Review articles are always considered secondary sources. Some types of secondary sources include:

• Textbooks
• Magazine/Journal Articles: Articles which interpret or review previous findings, or which present findings in way more accessible to the general public. They are not written by the original researcher. Examples would be Scientific American or Psychology Today. A "review article" may appear in a scholarly academic journal, but would be considered a secondary source.
• Histories
• Criticisms
• Encyclopedias

The information on this page is reused with permission from a Research Guide written by the Loyola University Chicago Reference Department.