The Hierarchy of Evidence

         
 

What is EBP?
Problems with the Definition
   
Why have EBP?

The Five Stages of EBP
   
The Question?
Background Questions
Foreground Questions
   

Finding the Evidence
The Hierarchy of Evidence
Tips on finding the evidence
   
Appraisal
   
Acting on Evidence

Evaluation & Reflection

The Hierarchy of Evidence

Evidence comes in many forms and varies in quality. Within research, there is a recognised hierarchy of reliability which can be used as a guide when considering the effectiveness of evidence. This is outlined in the table below:

Level
Description
Example
One

Strong evidence from at least
one systematic review of well
designed randomised controlled
trials
(RCTS)

Two
Evidence from at least one properly designed RCT of appropriate size
Three
Evidence from well designed trials without randomization: cohort, time series or matched case controlled studies
Articles published in peer-reviewed journals
Four
Evidence from well designed non-experimental studies from more than one centre or research group
Articles published in peer-reviewed journals
Five
Opinions from respected authorities, based on clinical evidence, descriptive studies or reports from committees
NICE guidelines
Evidence-based local procedures and care pathways
Six
Views of colleagues/peers
Nursing colleagues or members of the multidisciplinary team

It can be seen from the above table that the ideal source of evidence is Level One evidence in the form of a systematic review. Tips on finding the evidence offers more information on this subject.