| A |
The recommended action is supported by good evidence based on well designed studies (level of evidence I or II) directly applicable to the target |
| B |
The recommendation is supported by fair evidence based on well designed studies (level of evidence I, II, or III‐1) from which evidence can be extrapolated to the target population |
| or |
| The evidence is supported by weaker studies (level III or IV evidence) with overall consistency of results and directly relevant to the target population |
| C |
The recommendation is supported by expert opinion only, based either on weaker studies (level III‐2, III‐3, or IV evidence) from which evidence can be extrapolated to the target population, or consensus of expert opinion |
