Table 3:

Rating system for strength of recommendation and quality of evidence supporting the recommendation

Categories for the strength of each recommendation
Category	Definition
A	Good evidence to support a recommendation for use
B	Moderate evidence to support a recommendation for use
C	Poor evidence to support a recommendation for or against use
D	Moderate evidence to support a recommendation against use
E	Good evidence to support a recommendation against use
Categories for the quality of evidence on which recommendations are made
Stage	Definition
I	Evidence obtained from at least one properly randomized controlled trial
II	Evidence from at least one well designed, clinical trial without randomization, from cohort or case-controlled analytic studies preferably from more than one centre, from multiple time series or from dramatic results in uncontrolled experiments
III	Evidence from opinions of respected authorities on the basis of clinical experience, descriptive studies or reports of expert committees

Data from reference 37