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Evidence Hierarchy: Resource of the week #45

What is it?
The Evidence Hierarchy is a pyramid that aims to represent the relative quality of evidence, the hierarchy, that can be determined from various study types. It is suggested that not all evidence is the same, with different study types being subject to strengths, weaknesses, flaws and biases.
The study types listed at the top of the pyramid are considered to provide better quality evidence than those at the bottom.

There are a variety of different definitions of what is included in the pyramid and there is even some contention as to how useful it is.


Key Features
One of the key things to remember is that the pyramid is only giving you a representation of the quality of the study design, not whether the article you are looking at is “good” or “poor”. You will still need to critically appraise the research paper – for example you may be looking at a randomised controlled trial, but if it has not been carried out well, the article may not be helpful for you.

eTutorial
You can try our etutorial Evidence Hierarchy to learn more about the evidence hierarchy. We also include the description of some common study types.

More help?
You find more about the evidence hierarchy and evidence-based medicine in our book collection

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