Table 2 Class (Strength) of Recommendation [4]
From: Representation of cardiovascular magnetic resonance in the AHA / ACC guidelines
| Class of recommendation | Definition | Suggested phrases for writing recommendations |
|---|---|---|
| Class I (strong) | Benefit >> > Risk |
• is recommended • is indicated / useful / effective / beneficial • should be performed / administered / other • Comparative-Effectiveness phrases: − Treatment / strategy A is recommended / indicated in preference to treatment B − Treatment A should be chosen over treatment B |
| Class IIa (Moderate) | Benefit > > Risk |
• Is reasonable • Can be useful / effective / beneficial • Comparative-Effectiveness phrases − Treatment / strategy A is probably recommended / indicated in preference to treatment B − It is reasonable to choose treatment A over treatment B |
| Class IIb (Weak) | Benefit ≥ Risk |
• May / might be reasonable • May / might be considered • Usefulness / effectiveness is unknown / unclear / uncertain or not well established |
| Class III: No benefit (Moderate) | Benefit = Risk |
• Is not recommended • Is not indicated / useful / effective / beneficial • Should not be performed / administered / other |
| Class III: Harm (Strong) | Risk > Benefit |
• Potentially harmful • Causes harm • Associated with excess morbidity / mortality • Should not be performed / administered / other |