Strength of Recommendation Taxonomy
| Strength of Recommendation | Definition |
|---|---|
| A | Based on consistent and good-quality, patient-oriented evidence* |
| B | Based on inconsistent or limited-quality patient-oriented evidence* |
| C | Based on consensus, usual practice, opinion, or case series |
| Study Quality | Definition | Examples |
|---|---|---|
| Level 1 | Good-quality, patient-oriented evidence* | High-quality RCT |
| SR or MA of high-quality studies | ||
| High-quality prospective cohort study or SR or MA of such studies | ||
| Level 2 | Limited-quality, patient-oriented evidence* | Lower-quality clinical trial |
| Lower-quality cohort study | ||
| Retrospective cohort study | ||
| SR or MA of lower-quality studies or studies with inconsistent findings | ||
| SR or MA of lower-quality cohort studies or studies with inconsistent results | ||
| Case-control study | ||
| Level 3 | Other evidence | Consensus guidelines |
| Expert opinion | ||
| Case series |
Adapted from Ebell et al.22
↵* Patient-oriented evidence measures outcomes that matter to patients, such as morbidity, mortality, symptom improvement, and quality of life. Measures of disease activity or surrogate outcomes may or may not matter to the patient.
MA, meta-analysis; RCT, randomized controlled trial; SR, systematic review.