What is the hierarchy of scientific evidence?

A hierarchy of evidence (or levels of evidence) is a heuristic used to rank the relative strength of results obtained from scientific research. There is broad agreement on the relative strength of large-scale, epidemiological studies. More than 80 different hierarchies have been proposed for assessing medical evidence.

What is at the top of the hierarchy of evidence?

The hierarchy of evidence is a core principal of Evidence-Based Practice (EBP) and attempts to address this question. In most evidence hierachies current, well designed systematic reviews and meta-analyses are at the top of the pyramid, and expert opinion and anecdotal experience are at the bottom.

What is the lowest level of evidence?

expert opinions
Both systems place randomized controlled trials (RCT) at the highest level and case series or expert opinions at the lowest level. The hierarchies rank studies according to the probability of bias. RCTs are given the highest level because they are designed to be unbiased and have less risk of systematic errors.

What are the three dimensions of the hierarchy of evidence?

The proposed hierarchy of evidence focuses on three dimensions of the evaluation: effectiveness, appropriateness and feasibility. Research that can contribute valid evidence to each is suggested. To address the varying strengths of different research designs, four levels of evidence are proposed: excellent, good, fair and poor.

What are the four levels of evidence in research?

• The proposed hierarchy of evidence focuses on three dimensions of the evaluation: effectiveness, appropriateness and feasibility. Research that can contribute valid evidence to each is suggested. To address the varying strengths of different research designs, four levels of evidence are proposed: excellent, good, fair and poor.

How are evidence hierarchies used in evidence based medicine?

Evidence hierarchies are often applied in evidence-based practices and are integral to evidence-based medicine (EBM). In 2014, Stegenga defined a hierarchy of evidence as “rank-ordering of kinds of methods according to the potential for that method to suffer from systematic bias”.

Who was the first person to create a hierarchy of evidence?

Note that some sources identify Campbell & Stanley (1963) or Cochrane (1972) as presenting the first evidence hierarchy. While these are both clearly important sources and had a strong influence on the development of early hierarchies, it is my judgment that neither contain a hierarchy as such.