25
Recommendation Grading
Grade
Description
of Rec Benefit vs. Risk Quality of Evidence Implications
1-A Strong rec,
high-quality
evidence
Benefits clearly
outweigh risk
and burdens, or
vice versa
RCTs without
important
limitations or
overwhelming
evidence from
observational studies
Strong rec, can
apply to most
patients in most
circumstances
without
reservation
1-B Strong rec,
moderate-
quality
evidence
Benefits clearly
outweigh risk
and burdens, or
vice versa
RCTs with
important
limitations
(inconsistent results,
methodologic
flaws, indirect,
or imprecise) or
exceptionally strong
evidence from
observational studies
Strong rec, can
apply to most
patients in most
circumstances
without
reservation
1-C Strong rec,
lowquality
or very-
low-quality
evidence
Benefits clearly
outweigh risk
and burdens, or
vice versa
Observational
studies or case series
Strong rec but
may change when
higher quality
evidence becomes
available
2-A Weak rec,
highquality
evidence
Benefits closely
balanced with
risks and burdens
RCTs without
important
limitations or
overwhelming
evidence from
observational studies
Weak rec, best
action may differ
depending on
circumstances
or patients' or
societal values
2-B Weak rec,
moderate-
quality
evidence
Benefits closely
balanced with
risks and burdens
RCTs with
important limitations
(inconsistent results,
methodologic
flaws, indirect,
or imprecise) or
exceptionally strong
evidence from
observational studies
Weak rec, best
action may differ
depending on
circumstances
or patients' or
societal values
2-C Weak rec,
lowquality
or very-
low-quality
evidence
Uncertainty in
the estimates of
benefits and risk,
and burdens;
Risk, benefit, and
burdens may be
closely balanced
Observational
studies or case series
Very weak recs;
Other alternatives
may be reasonable
RCTs, Randomized controlled trials; rec, recommendation.
Modified from Guyatt G, Gutterman D, Baumann MH, Addrizzo-Harris D, Hylek EM, Phillips B,
et al. Grading strength of recommendations and quality of evidence in clinical guidelines: Report
from an American College of Chest Physicians task force. Chest 2006;129:174-81.
