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
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:


Strong evidence from at least
one systematic review of well
designed randomised controlled

Evidence from at least one properly designed RCT of appropriate size
Evidence from well designed trials without randomization: cohort, time series or matched case controlled studies
Articles published in peer-reviewed journals
Evidence from well designed non-experimental studies from more than one centre or research group
Articles published in peer-reviewed journals
Opinions from respected authorities, based on clinical evidence, descriptive studies or reports from committees
NICE guidelines
Evidence-based local procedures and care pathways
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.