Table 1.

Strength of recommendations and quality of evidence

Category/grade	Definition
Strength of recommendation
Strong recommendation (A)	Considering the benefits and risks of the treatment, the level of evidence, values and preferences, and resources, it is strongly recommended in most clinical situations.
Conditional recommendation (B)	The use of the treatment may vary depending on the clinical situation or patient/social value, so it is recommended to use it selectively or conditionally.
Against recommendation (C)	The risk of the treatment may outweigh the benefit and, taking into account the clinical situation or patient/social value, implementation is not recommended.
Inconclusive (I)	Considering the benefits and risks of the treatment, values and preferences, and resources, the level of evidence is too low, the scale of benefit/risk is too uncertain, or the variability is large, so the decision to implement the intervention is not made. This means that we cannot recommend or object to the use of treatment, so the decision is at the clinician’s discretion.
Expert consensus (E)	Although clinical evidence is insufficient, use is recommended in accordance with clinical experience and expert consensus when considering the benefits and risks of the treatment, the level of evidence, values and preferences, and resources.
Quality of evidence
High	We are confident that the estimate of the effect is close to the actual effect.
Moderate	The estimate of the effect appears to be close to the actual effect, but may vary considerably.
Low	The confidence in the estimate of the effect is limited. The actual effect may differ significantly from the estimated effect.
Very low	There is little confidence in the estimate of the effect. The actual effect will differ significantly from the estimated effect.