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BI155 - Ecology & Evolution Lab - Robertson: Primary & Secondary Sources

A research guide for students looking for sources for their ecology & evolution "aquatic locomotion" lab.

Test Yourself!

Below are links to several primary and secondary-source articles on fish, swimming, and hydrodynamics, typical of what you may find when searching for articles for this assignment. Test yourself by examining these articles and their abstracts.

Can you tell which are primary, and which are secondary sources?

What is a Review Article?

Review articles are a special kind of secondary source that are often found in scholarly and peer-reviewed journals.

While not primary sources/original research, they are often still scholarly, peer-reviewed (and lengthy) sources.

They review, evaluate, summarize, and provide context for multiple primary sources, and are often an excellent source for determining the current state of research on a given topic. Sometimes, the review authors draw conclusions from their analysis of the articles they review.

Review articles are also especially useful for their bibliographies, which provide citations to the primary sources being reviewed.

Clues (key words/phrases to look for in abstracts or article titles):

  • review ("...the purpose of this article is to review the current knowledge..."; "this article aims to review...")
  • literature review or literature survey ("this article presents a literature review...")
  • review article or systematic review

Note: A review article is NOT the same as a book review

Note: Systematic reviews and meta-analyses are a special kind of review article that is especially highly regarded in evidence-based health care.

Check out this article for an example of a review article:

Ask MUlibrarian

What is a Primary Source? What is a Secondary Source?

Primary Sources

In the sciences primary sources include original materials that report original research, ideas, new information, or scientific discoveries and are the first formal appearance of that research. They report results and data which are then used as the basis for other research. They are not interpretations or evaluations of the research by other authors (they are "unfiltered"), though they will usually cite other primary research and secondary review articles to provide a context for their research.

Commonly Include:

  • Articles in scholarly, peer-reviewed journals
  • Articles with clearly defined sections (Abstract, Introduction, Methods, Results, Discussion/Conclusion, Works Cited)
  • Scientific conference papers
  • Dissertations or theses
  • Lab notebooks
  • Patents
  • Multiple authors

Clues (key words/phrases to look for in abstracts):

  • research, study ("in this study, we..."), experiment ("in this experiment, we...")
  • abstract, introduction, methods/methodology, results, discussion, conclusion, works cited/bibliography/references
  • data, findings
  • peer-reviewed

Video: Primary Sources Natural Sciences (4:40), from Hammersly Library Western Oregon University.


Secondary Sources

Secondary sources report, summarize, review, comment on, interpret, analyze, or evaluate primary sources.  Secondary sources are not evidence in themselves, but rather comment on and discuss evidence. They are a "filter" through which primary sources are often viewed and can provide context and plain-language summaries of articles.

Commonly Include:

  • Newspaper articles
  • Popular or special interest magazine articles (for example, Time, Discover, The Economist)
  • Trade or professional publication articles (for example, Chemical & Engineering News)
  • Publications about the significance of research or experiments
  • Reviews or summaries of the results of several experiments, studies, or trials
  • Letters to the editor, editorials
  • Books

Clues (key words/phrases to look for in abstracts):

  • review (“this paper reviews studies…”)
  • reports (“this article reports the results of several studies…”)
  • explains ("this article explains the results of a new study...")
  • meta-analysis, systematic review, review of the literature (for more on these types of sources, see this box)
  • editorial, letter to the editor, commentary

Note: Secondary sources can appear in peer-reviewed and scholarly journals, as well as less scholarly publications, because even peer-reviewed journals contain reviews, editorials, and news items.


Tertiary Sources

Tertiary sources consist of information which is a distillation and collection of primary and secondary sources. The information in these sources is condensed and reformatted from the original

Commonly Include:

  • Textbooks
  • Reference books (Encyclopedias, etc.)