Table 2. Strength of recommendation.

Grade	Definition*	Recommendations for practice
A	The practice is recommended. There is high certainty that the net benefit is substantial.	Offer or provide the practice.
B	The practice is recommended. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.	Offer or provide the practice.
C	The practice is not routinely recommended. There may be considerations that support the practice at an individual level. There is at least moderate certainty that the net benefit is small.	Offer or provide this service for selected patients depending on individual circumstances.
D	The practice is not recommended. There is moderate or high certainty that the practice has no net benefit, or that the damages outweigh the benefits.	Discourage the use of this practice.
I	The current evidence is insufficient to assess the balance between its benefits and harms. The evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.	Read the introductory text containing evidence obtained in the literature review that supports this recommendation. If the practice is offered, the patients should understand that there is uncertainty in the balance between benefits and harms.

^*The United States Preventive Services Task Force (USPSTF) defines certainty as the “likelihood that the USPSTF's assessment of the net benefit of a preventive practice is correct.” The net benefit is defined as the benefit minus the practice injury when implemented in a general population.2