These different resources will not all have the same "weight" in terms of reliability and trustworthiness. To assist you in determining what is the most reliable, the levels of evidence hierarchies will guide you. Evidence Hierarchies are systems used to rank evidence according to certain criteria. There are many hierarchies, including the examples on this page.
Hierarchy of evidence: a framework for ranking evidence evaluating healthcare interventions
Level of evidence Term Paper Example | Topics and Well Written Essays - words
Meet with a librarian for one-on-one research assistance. Level I : Evidence from a systematic review of all relevant randomized controlled trials RCT's , or evidence-based clinical practice guidelines based on systematic reviews of RCT's. Level III : Evidence obtained from well-designed controlled trials without randomization, quasi-experimental. Level IV : Evidence from well-designed case-control and cohort studies.
Not all evidence is the same, and appraising the quality of the evidence is part of evidence-based practice research. The hierarchy of evidence is typically represented as a pyramid shape, with the smaller, weaker and more abundant research studies near the base of the pyramid, and systematic reviews and meta-analyses at the top with higher validity but a more limited range of topics. Several versions of the evidence pyramid have evolved with different interpretations, but they are all comprised of the types of evidence discussed on this page. A systematic review is a type of publication that addresses a clinical question by analyzing research that fits certain explicitly-specified criteria. The criteria for inclusion is usually based on research from clinical trials and observational studies.
Studies in which randomization occurs represent a higher level of evidence than those in which subject selection is not random. Controlled studies carry a higher level of evidence than those in which control groups are not used. It looks like you're using Internet Explorer 11 or older.