The Strength of Recommendation Taxonomy
THE JOURNAL OF FAMILY PRACTICE (JFP) uses a simplified rating system called the Strength of Recommendation Taxonomy (SORT). In general, only the Practice Recommendations that appear at the beginning of each Applied Evidence article require a grade of the "Strength of Recommendation." Recommendations should be based on the highest quality evidence available. For example, vitamin E was found in some cohort studies (level 2 study quality) to have a benefit for cardiovascular protection, but good-quality randomized trials (level 1) have not confirmed this effect. Therefore, it is preferable to base clinical recommendations in a manuscript on the level 1 studies.
Strength of recommendation | Definition |
A | Recommendation based on consistent and good-quality patient-oriented evidence.* |
B | Recommendation based on inconsistent or limited-quality patient-oriented evidence.* |
C | Recommendation based on consensus, usual practice, opinion, disease-oriented evidence,* or case series for studies of diagnosis, treatment, prevention, or screening. |
Use the following scheme to determine whether a study measuring patient-oriented outcomes is of good or limited quality, and whether the results are consistent or inconsistent between studies.
Type of study | |||
Study quality | Diagnosis | Treatment/prevention/screening | Prognosis |
Level 1—good-quality patient-oriented evidence | Validated clinical decision rule SR/meta-analysis of high-quality studies High-quality diagnostic cohort study† | SR/meta-analysis of RCTs with consistent findings. High-quality individual RCT.‡ All-or-none study§ | SR/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 SR/meta-analysis of lower-quality studies or studies with inconsistent findings. Lower-quality diagnostic cohort study or diagnostic case-control study§ | SR/meta-analysis of lower-quality clinical trials or of studies with inconsistent findings. Lower-quality clinical trial.‡ Cohort study. Case-control study | SR/meta-analysis of lower-quality cohort studies or with inconsistent results. Retrospective cohort study or prospective cohort study with poor follow-up. 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 | ||
* Patient-oriented evidence measures outcomes that matter to patients: morbidity, mortality, symptom improvement, cost reduction, and quality of life. Disease-oriented evidence measures intermediate, physiologic, or surrogate end points that may or may not reflect improvements in patient outcomes (ie, blood pressure, blood chemistry, physiologic function, and pathologic findings). † High-quality diagnostic cohort study: cohort design, adequate size, adequate spectrum of patients, blinding, and a consistent, well-defined reference standard. ‡ High-quality RCT: allocation concealed, blinding if possible, intention-to-treat analysis, adequate statistical power, adequate follow-up (>80%). § In an all-or-none study, the treatment causes a dramatic change in outcomes, such as antibiotics for meningitis or surgery for appendicitis, which precludes study in a controlled trial.
RCT, randomized controlled trial; SR, systematic review. | |||