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Types and Levels of Evidence for Nutrition/Dietetic Research

Describes different types of evidence and provides strategies for finding specific types of articles for Nutrition students

Let's look at the hierarchy of scientific evidence.

The following types of research are listed as primary vs. secondary:

  • Meta-Analysis and Systematic Reviews (Secondary/Reviews)
  • Randomized Controlled Trials (Primary/Original Research Articles)
  • Cohort Studies (Primary/Original Research Articles)
  • Case-Control Studies (Primary/Original Research Articles)
  • Cross-sectional studies (Primary/Original Research Articles)
  • Animal Trials and In Vitro Studies (Primary/Original Research Articles)
  • Case Reports, opinion pieces, and letters (Primary)

Next, look at the Hierarchy of Scientific Evidence chart:

hierarchy of scientifc evidence

Infographic Transcript

Here is a list of evidence from highest to weakest:

1. Meta-analyses & systematic reviews

2. Randomized controlled trials

3. Cohort studies

4. Case-control studies

5. Cross sectional studies

6. Animal trials & in vitro studies

7. Case reports, opinion papers, and letters

 

Attribution

This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

Benjamin Cunningham/Logic of Science

Source: https://commons.wikimedia.org/wiki/File:Hierarchy_of_Evidence.png