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EXSC 200: Introductory Research Methods

Primary/Secondary? Popular/Scholarly? What's the difference?

Let's talk a little bit about High Intensity Interval Training (HIIT). Do you know what it is?

Let's take a look at a bunch of sources below (some of which are peer-reviewed scholarly articles, and some of which are not!) and do an evaluation of these different types of sources. For each of the sources below, let's consider: 

  • Is it a peer-reviewed?
  • Is it an original research article (also known as primary literature)?
  • What's your assessment of the credibility/reliability of the source, and what factors would you use to make that evaluation?

Types of Sources

  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  • Not peer-reviewed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  • (In the social sciences and humanities, these can be historical documents, art, speeches, etc.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

Chart with Heirarchy of Evidence. Image transcription below.

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

PICO

P

Patient, Population, or Problem

What’s the issue- is it pain, injury, disease? Who is the population- age, gender, demographics?

I

Intervention

What can you DO about the issue? Is there medication, treatment, diagnostic procedure?

C

Comparison or Control (if appropriate)

What are the alternatives to the interventions discussed above?

O

Outcome you would like to measure or achieve

What about this issue could be measured, improved, or affected?

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