For clinical questions, articles with the highest quality of evidence are best. The pyramid represents the Levels of Evidence Hierarchy. Studies are assigned to a level based on their design and strength of recommendation.
Source: Wood, G. L, & Haber, J. (2014). Nursing research: Methods and critical appraisal of evidence-based practice (8ed). St. Louis: Mosby/Elsevier
Types of studies
Sources consulted: Jewell, D. V. (2011). Guide to evidence-based physical therapist practice (2nd ed.). Sudbury, MA: Jones & Bartlett Learning. ; Woolf, S. H., Grol, R., Hutchinson, A., Eccles, M., & Grimshaw, J. (1999). Potential benefits, limitations, and harms of clinical guidelines. BMJ : British Medical Journal, 318(7182), 527–530. ; Koffel, J. (2016). Understanding research study designs. Retrieved September 12, 2016, from https://hsl.lib.umn.edu/biomed/help/understanding-research-study-designs