Collins Memorial Library: PH 601: Foundations of Public Health: Types of Sources

Types of Sources in the Health Sciences

	Scholarly Sources	Popular Sources
Primary Sources	Peer Reviewed Published in a scholarly journal Contains first-hand reports of research presented by the person or team that did the research. We cite these to reference the results and discussion of their research.	Not peer-reviewed Published anywhere E.g. Someone doing their own experiment and posting it on their blog E.g. A news organization conducting their own research and releasing their own data visualizer (In the social sciences and humanities, these can be historical documents, art, speeches, etc. But we don't use these in the sciences) We don't cite these because they haven't been peer reviewed.
Secondary Sources	Peer reviewed Published in a scholarly journal Draw on other scholarly publications to come up with their own conclusions There are two main types: "Narrative Reviews" and "Systematic Reviews/Meta Analyses" We cite systematic reviews because they mathematically compare studies on the same topic to determine an overall trend Narrative reviews do not systematically compare studies, only mention them, so we generally cite primary-source studies instead of these. Narrative reviews are generally considered "expert opinion", which is weaker evidence than the results of a study.	Reports on and draws conclusions from primary scholarly sources. Published anywhere News article, press release, trade publication, blog post, etc. We don't cite these because if they just report on a primary source, we should go to the primary source itself, and if they provide analysis, that analysis hasn't been peer reviewed.
Tertiary Sources	Gives an overview of information accumulated from primary and secondary sources Does not provide original interpretations or analyses You use these in the beginning of your research process to learn about your topic. You may or may not cite these depending on your audience: Facts that would be common knowledge to your audience don't need to be cited.	Gives an overview of information gathered from primary and secondary sources Does not provide original interpretations or analysis Not operated by a scholarly institution or organization. Wikipedia. You won't cite these, but you'll use them in the beginning of your research process to learn about your topic.

Hierarchy of Evidence

Biomedical research works with particular types of sources, in a hierarchy of evidence. This information is useful in Public Health when you are evaluating the strength of evidence. Note, however, that Public Health also makes use of research in the social sciences. In some disciplines in the social sciences, like psychology, the research hews very closely to the scientific understanding of types of sources, while in other disciplines (sociology, political science), standards of evidence and the style of argumentation are different.

Image Transcription:

The hierarchy of evidence from from highest to lowest:

Secondary, pre-appraised, or filtered:
- Clinical Practice Guidelines
- Meta-Analyses & Systematic Reviews
Primary Studies:
- Randomized Controlled Trial (Prospective, tests treatment)
- Observational Studies:
  - Cohort Studies (Prospective, exposed cohort is observed for outcome)
  - Case Control Studies (Retrospective, subjects already of interest looking for risk factors)
No design:
- Case Report or Case Series, Narrative Reviews, Expert Opinions, Editorials
No humans involved:
- Animal and Laboratory Studies