TABLE 5.

System for ranking recommendations in clinical guidelines recommended by IDSA^a

Category, grade	Definition
Strength of recommendation
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 use
D	Moderate evidence to support a recommendation against use
E	Good evidence to support a recommendation against use
Quality of evidence
I	Evidence from one or more properly randomized, controlled trials
II	Evidence from one or more well-designed clinical trials, without randomization; from cohort or case-controlled analytic studies (preferably from more than one center); from multiple time series; or from dramatic results from uncontrolled experiments
III	Evidence from opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees

^aReprinted from reference 51 with permission.