Institute:Office of National Coordinator (ONC) Workforce Training Curriculum
Component:The Culture of Health Care
Unit:Evidence-Based Practice
Lecture:Definition and application of EBM
Phrasing the clinical question
Slide content:Hierarchy of EvidenceThe 4S Model (Haynes, 2001) Subsequently updated to 5S (Haynes, 2005) and 6S ( DiCenso , 2009) models, but 4S is preferred 5.2 Figure: adapted from Hayness 4S model of the Hierarchy of Evidence, 2001 8
Slide notes:8 Another way to look at evidence is to look at the hierarchy of evidence. One approach shows the different types of evidence that clinicians use for decision making. This model was developed by Haynes and originally started as the 4S model, the simplest version. He subsequently divided some of the levels into additional levels and updated the model to 5S and then 6S, but the basic 4S model is the most popular. The foundation, or first level, of evidence is studiesoriginal research thats published in medical journals. For many topics, especially common diseases and common treatments, there are numerous studies, so we need to synthesize them. Thus the next level in the hierarchy is syntheses [ sin - thuh - seez ]. The best syntheses are systematic reviews . Also called evidence reports, they systematically review all of the evidence for a given clinical question. Syntheses, however, can be quite lengthy, and a busy clinician usually needs to understand the gist of the evidence. Thus the next level in the hierarchy is synopses [ si- nop -seez ], which are sometimes called evidence-based abstractions, where key points are abstracted from comprehensive syntheses. Finally, the highest level of evidence is systems, where there is actionable knowledge, or knowledge taken from the synopses that can be put into a logical form and used ideally by electronic systems to automatically guide decision making.