Levels of Evidence
When searching for the best available evidence, a hierarchy exists regarding the level and strength of evidence. As you review the journal articles, select those that are based on highest level of evidence, such as a Meta-Analyses or a Systematic Review.
Heirarchies of Evidence
The type of question will often dictate the best study design to address the question. In the absence of the best study design, move down the EBP Evidence Pyramid:
Image Source: https://guides.norwich.edu/EBP/criticalappraisal
Study Definitions
Meta-Analysis: A meta-analysis synthesizes data from numerous studies to calculate and combine the overall effect sizes.
Systematic Review: A summary of the medical literature that uses explicit methods to perform a comprehensive literature search & critical appraisal of individual studies to answer a predefined research question.
Randomized Controlled Trial: Participants are randomly allocated into experimental or control groups to minimize bias.
Cohort Study: Identifies participants who currently have a certain condition or receive a treatment and are followed over time & compared with another group of people who are not affected by the condition.
Case Control Study: Identifies participants who have a certain outcome (cases) & participants without that
outcome (controls).
Case Report/Case Series: A report on one or more participants with a particular outcome.
Source: DynaMed, 7 Steps to the Perfect PICO(T) Score: Evidence-Based Nursing Practice