====== Quality of a body of evidence ======

The [[quality]] of a body of [[evidence]] refers to the degree to which the available evidence supports a particular [[conclusion]] or [[decision]]. In general, high-quality evidence is considered to be more reliable and trustworthy than low-quality evidence.

Several factors can affect the [[quality of evidence]], including the [[design]] of the [[study]], the size and representativeness of the [[study sample]], the accuracy and precision of the measurements used, the level of [[bias]] and [[confounding]], and the [[consistency]] of the findings across different studies.

The hierarchy of [[evidence-based medicine]] is often used to classify the quality of evidence, with [[systematic review]]s and [[meta-analysis]] of [[randomized controlled trial]]s (RCTs) generally considered to provide the highest-quality evidence, followed by individual RCTs, observational studies, and [[expert opinion]]. However, the quality of evidence can also depend on the specific context and the specific question being asked.
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The [[GRADE]] approach is a [[system]] for [[rating]] the [[quality of a body of evidence]] in [[systematic review]]s and other evidence syntheses, such as health technology assessments, and guidelines and grading recommendations in health care. GRADE offers a transparent and structured process for developing and presenting evidence summaries and for carrying out the steps involved in developing recommendations. It can be used to develop [[clinical practice guidelines]] (CPG) and other health care [[recommendations]] (e.g. in public health, health policy and systems and coverage decisions).