Treatments should ideally be based on the best evidence available.  With rare conditions, information (evidence) may come from a hand-full of cases, with more common conditions being more heavily studied.  With evidence-based practice (EBP) or evidence-based medicine (EBM), healthcare is based on statistically proven methods that have been shown to be effective.  There are varying levels of evidence available.  Please see the EBM Pyramid below to learn about the different levels of evidence.

The EBM Pyramid displays the hierarchy of levels of evidence based on the type of resource you are using. As you go up the EBM Pyramid, the level of evidence becomes stronger.  See the EBM Pyramid below.

Or see this guide which includes the EBP Pyramid as well as a list of resources to help you find information types for each level of the EBP Pyramid.

Suggested tutorials to learn about evidence-based practice include: