Table 1.

Classification Scheme for Grading Evidence (Guyatt et al., 2006)

Grade 1A	Strong recommendation, high-quality evidence benefits clearly outweigh risks and burden or vice versa
Grade 1B	Strong recommendation, moderate-quality evidence benefits clearly outweigh risks and burdens or vice versa
Grade 1C	Strong recommendation, low-quality or very low-quality evidence benefits clearly outweigh risks and burdens or vice versa
Grade 2A	Weak recommendation, high-quality evidence benefits closely balanced with risks and burdens
Grade 2B	Weak recommendation, moderate-quality evidence benefits closely balanced with risks and burdens
Grade 2C	Weak recommendation, low-quality or very low-quality evidence, uncertainty in the estimates of benefits, risks, and burden; benefits, risk, and burden may be closely balanced