Skip to main content

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