AFP uses the Strength-of-Recommendation Taxonomy (SORT),1 to label key recommendations in clinical review articles. In general, only key recommendations are given a Strength-of-Recommendation grade. Grades are assigned on the basis of the quality and consistency of available evidence. Table 1 shows the three grades recognized.
An alternative way to understand the significance of a strength-of-recommendation grade is through the algorithm generally followed by authors and editors in assigning grades based on a body of evidence (Figure 1). While this algorithm provides a general guideline, authors and editors may adjust the strength of recommendation based on the benefits, harms, and costs of the intervention being recommended.
|Strength of recommendation||Basis for recommendation|
|A||Consistent, good-quality patient-oriented evidence*|
|B||Inconsistent or limited-quality patient-oriented evidence*|
|C||Consensus, disease-oriented evidence,** usual practice, expert opinion, or case series for studies of diagnosis, treatment, prevention, or screening|
|Level 1: good-quality, patient-oriented evidence||Validated clinical decision rule|
Systematic review/meta-analysis of high-quality studies
High-quality diagnostic cohort study*
|Systematic review/meta-analysis or RCTs with consistent findings|
High-quality individual RCT†
|Systematic review/meta-analysis of good-quality cohort studies|
Prospective cohort study with good follow-up
|Level 2: limited-quality patient-oriented evidence||Unvalidated clinical decision rule|
Systematic review/meta-analysis of lower quality studies or studies with inconsistent findings
Lower quality diagnostic cohort study or diagnostic case-control study
|Systematic review/meta-analysis of lower quality clinical trials or of studies with inconsistent findings|
Lower quality clinical trial
|Systematic review/meta-analysis of lower quality cohort studies or with inconsistent results|
Retrospective cohort study or prospective cohort study with poor follow-up
|Level 3: other evidence||Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series for studies of diagnosis, treatment, prevention, or screening|
|Consistent||Most studies found similar or at least coherent conclusions (coherence means that differences are explainable).|
If high-quality and up-to-date systematic reviews or meta-analyses exist, they support the recommendation.
|Inconsistent||Considerable variation among study findings and lack of coherence|
If high-quality and up-to-date systematic reviews or meta-analyses exist, they do not find consistent evidence in favor of the recommendation.