Am Fam Physician. 2011;83(8):1004-1005
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.
| 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 |
| Study quality | Diagnosis | Treatment/prevention/ screening | Prognosis |
|---|---|---|---|
| Level 1: good-quality, patient-oriented evidence | Validated clinical decision rule | SR/meta-analysis or RCTs with consistent findings | SR/meta-analysis of good- quality cohort studies |
| SR/meta-analysis of high-quality studies | |||
| High-quality diagnostic cohort study* | High-quality individual RCT† | Prospective cohort study with good follow-up | |
| All-or-none study‡ | |||
| Level 2: limited-quality patient-oriented evidence | Unvalidated clinical decision rule | SR/meta-analysis of lower quality clinical trials or of studies with inconsistent findings | SR/meta-analysis of lower quality cohort studies or with inconsistent results |
| SR/meta-analysis of lower quality studies or studies with inconsistent findings | |||
| Lower quality diagnostic cohort study or diagnostic case-control study | Lower quality clinical trial | Retrospective cohort studyor prospective cohort study with poor follow-up | |
| Cohort study | |||
| Case-control study | Case-control study | ||
| Case series | |||
| 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). | |
| or | ||
| 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 | |
| or | ||
| If high-quality and up-to-date systematic reviews or meta-analyses exist, they do not find consistent evidence in favor of the recommendation. | ||
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.
