Question

What criteria are used to grade the different levels of evidence?

Answer 1

Ans) GRADE has four levels of evidence – also known as certainty in evidence or quality of evidence: very low, low, moderate, and high. Evidence from randomised controlled trials starts at high quality and, because of residual confounding, evidence that includes observational data starts at low quality.

- 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."

Level of evidence (LOE):

Level I

Evidence from a systematic review or meta-analysis of all relevant RCTs (randomized controlled trial) or evidence-based clinical practice guidelines based on systematic reviews of RCTs or three or more RCTs of good quality that have similar results.

Level II

Evidence obtained from at least one well-designed RCT (e.g. large multi-site RCT).

Level III

Evidence obtained from well-designed controlled trials without randomization (i.e. quasi-experimental).

Level IV

Evidence from well-designed case-control or cohort studies.

Level V

Evidence from systematic reviews of descriptive and qualitative studies (meta-synthesis).

Level VI

Evidence from a single descriptive or qualitative study.

Level VII

Evidence from the opinion of authorities and/or reports of expert committees.