PRIMARY scientific sources refer to original reports of research reviewed by experts (via the "peer review process") and published in scholarly journals. They reflect the individual viewpoint of a participant or observer. Primary literature in the sciences is written in a systematic manner and typically includes the following sections: abstract, introduction, literature review, materials and methods, results, discussion, acknowledgements, and references (and sometimes an appendix or data sets).

TYPES OF PRIMARY SCIENTIFIC SOURCES INCLUDE: 
1) Original Research Studies

2) Clinical Trials (e.g. randomized control trials)

Watch this 3-minute video to learn more about the PEER REVIEW PROCESS! 

In order to use a primary source effectively, you should know some things about it. Consider these questions when determining to use a primary source for your research:

Who is the author/creator? What can you find out about them? 

When was it created / published? (Is it actually primary?)

Why was it created? 

Where is it published? Is it a reputable source?

What is the larger context of the source? What else was going on in the region/world at the time it was created? (HINT: Use secondary sources to confirm)

What sources does this one use? How about keywords? Can you use these to find other works? 

What questions do you have after studying the source? What else do you need/want to know? 

SECONDARY scientific sources are works that interpret or analyze original PRIMARY research. 

TYPES OF SECONDARY SCIENTIFIC SOURCES INCLUDE: 
1) Review articles (systematic, scoping, meta analysis... see below)

2) Editorials (see below)

3) Textbooks

4) Dissertations

Review article: A review article provides a synthesis of existing research on a particular topic. They are not reports of original research. Review Articles are excellent resources for discovering what the key articles are for a given topic. 

Systematic review:  Systematic reviews are methodical reviews and analyzes of literature pertinent to a specific research question. Systematic reviews aim to identify and synthesize all of the primary research related to a question in an unbiased, reproducible way to provide evidence for practice and decision-making. 

Meta-analysis:  Meta-analysis combine data from unrelated independent studies into a new analysis using a variety of statistical methods and procedures. The aim of a meta-analysis is to combine disparate data sets to draw a conclusion with greater statistical power than that of the individual studies. 

Commentary (editorials): Articles expressing a authors view about a particular issue are often published in academic journals as commentary, editorial, opinion or perspective pieces. Some commentary pieces are thoroughly researched, citing peer reviewed literature.  While other pieces are basic orations of an individual's perspective and do not reference additional sources. Commentary articles often appear in peer-reviewed journals but are not empirical studies.