What type of evidence source is at the pinnacle of most evidence hierarchies?
IntroductionOne way to organize the different types of evidence involved in evidence-based practice research is the levels of evidence pyramid. The pyramid includes a variety of evidence types and levels. Show
The levels of evidence pyramid provides a way to visualize both the quality of evidence and the amount of evidence available. For example, systematic reviews are at the top of the pyramid, meaning they are both the highest level of evidence and the least common. As you go down the pyramid, the amount of evidence will increase as the quality of the evidence decreases. EBM Pyramid and EBM Page Generator, copyright 2006 Trustees of Dartmouth College and Yale University. All Rights Reserved. Filtered ResourcesFiltered resources appraise the quality of studies and often make recommendations for practice. The main types of filtered resources in evidence-based practice are:
Scroll down the page to the Systematic reviews, Critically-appraised topics, and Critically-appraised individual articles sections for links to resources where you can find each of these types of filtered information. Systematic reviewsAuthors of a systematic review ask a specific clinical question, perform a comprehensive literature review, eliminate the poorly done studies, and attempt to make practice recommendations based on the well-done studies. Systematic reviews include only experimental, or quantitative, studies, and often include only randomized controlled trials. You can find systematic reviews in these filtered databases:
You can also find systematic reviews in this unfiltered database:
To learn more about finding systematic reviews, please see our guide: Critically-appraised topicsAuthors of critically-appraised topics evaluate and synthesize multiple research studies. Critically-appraised topics are like short systematic reviews focused on a particular topic. You can find critically-appraised topics in these resources:
Critically-appraised individual articlesAuthors of critically-appraised individual articles evaluate and synopsize individual research studies. You can find critically-appraised individual articles in these resources:
To learn more about finding critically-appraised individual articles, please see our guide: Unfiltered resourcesYou may not always be able to find information on your topic in the filtered literature. When this happens, you'll need to search the primary or unfiltered literature. Keep in mind that with unfiltered resources, you take on the role of reviewing what you find to make sure it is valid and reliable. Note: You can also find systematic reviews and other filtered resources in these unfiltered databases. The Levels of Evidence Pyramid includes unfiltered study types in this order of evidence from higher to lower:
You can search for each of these types of evidence in the following databases:
TRIP database
Background information & expert opinionBackground information and expert opinions are not necessarily backed by research studies. They include point-of-care resources, textbooks, conference proceedings, etc.
What type of evidence source is at the pinnacle of most evidence hierarchy?Systematic reviews are at the pinnacle of the hierarchy (Level I), because the strongest evidence comes from careful syntheses of multiple studies. The next highest level (Level II) includes individual randomized controlled trials (RCTs).
What is the highest level of evidence?When searching for evidence-based information, one should select the highest level of evidence possible--systematic reviews or meta-analysis. Systematic reviews, meta-analysis, and critically-appraised topics/articles have all gone through an evaluation process: they have been "filtered".
What is a hierarchy of evidence in research?Levels of evidence (sometimes called hierarchy of evidence) are assigned to studies based on the methodological quality of their design, validity, and applicability to patient care. These decisions gives the "grade (or strength) of recommendation."
Why is a systematic review the highest level of evidence?Bias (of which there are many types) can confound the outcomes of a study such that it may over or underestimate the true treatment effect. Therefore, systematic reviews of randomized control trials which are designed specifically to minimize bias from confounding factors have become the highest level of evidence.
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