Skip to Main Content

Biomedical Sciences: Primary and Secondary Sources

Primary and Secondary Sources

The fundamental question to ask to determine whether a source is primary or secondary in science is, "Did the authors of this paper collect the data?" 

Primary source—the work represents original research

Secondary source—the work reflects on, synthesizes, or reviews the research of others. 

Clues that the article is a primary source: 

  • Analyzes the data collected by the authors. 
  • Often extremely narrow in scope.
  • Abstract may include phrases like "we observed," "sampling was conducted," etc. 
  • Usually includes a methods section. 
  • Will include a review of past work by others, but this is meant to provide context for original data collection and analysis. 
The article below is a primary source because the authors collected the data themselves.


Example of primary source because authors collected the data, as indicated by "this study reports on monthly sampling" in the abstract.

Clues that the article is a secondary source: 

  • Describes the work of other scientists.
  • Surveys the state of research within a narrow field of study. 
  • Title or abstract includes the terms reviewliterature review, or meta-analysis
  • May not include a methods section. 
The article below is a secondary source, not only because it says "review" in the title, but also because the article mentions it is a survey of other articles. 

Review Article Example


Review Snippet