Editing Evidence-based medicine (section)

=== Categories of recommendations ===
In guidelines and other publications, recommendation for a clinical service is classified by the balance of risk versus benefit and the level of evidence on which this information is based. The U.S. Preventive Services Task Force uses the following system:<ref>{{cite journal | vauthors = Sherman M, Burak K, Maroun J, Metrakos P, Knox JJ, Myers RP, Guindi M, Porter G, Kachura JR, Rasuli P, Gill S, Ghali P, Chaudhury P, Siddiqui J, Valenti D, Weiss A, Wong R | display-authors = 6 | title = Multidisciplinary Canadian consensus recommendations for the management and treatment of hepatocellular carcinoma | journal = Current Oncology | volume = 18 | issue = 5 | pages = 228–240 | date = October 2011 | pmid = 21980250 | pmc = 3185900 | doi = 10.3747/co.v18i5.952 }}</ref>
* Level A: Good [[scientific evidence]] suggests that the benefits of the clinical service substantially outweigh the potential risks. Clinicians should discuss the service with eligible patients.
* Level B: At least fair scientific evidence suggests that the benefits of the clinical service outweighs the potential risks. Clinicians should discuss the service with eligible patients.
* Level C: At least fair scientific evidence suggests that the clinical service provides benefits, but the balance between benefits and risks is too close for general recommendations. Clinicians need not offer it unless individual considerations apply.
* Level D: At least fair scientific evidence suggests that the risks of the clinical service outweigh potential benefits. Clinicians should not routinely offer the service to asymptomatic patients.
* Level I: Scientific evidence is lacking, of poor quality, or conflicting, such that the risk versus benefit balance cannot be assessed. Clinicians should help patients understand the uncertainty surrounding the clinical service.

GRADE guideline panelists may make strong or weak recommendations on the basis of further criteria. Some of the important criteria are the balance between desirable and undesirable effects (not considering cost), the quality of the evidence, values and preferences and costs (resource utilization).<ref name="GRADE Handbook" />

Despite the differences between systems, the purposes are the same: to guide users of clinical research information on which studies are likely to be most valid. However, the individual studies still require careful critical appraisal<ref>{{Cite web |title=Appraise the evidence {{!}} BMJ Best Practice |url=https://bestpractice.bmj.com/info/us/toolkit/learn-ebm/appraise-the-evidence/ |access-date=2025-02-10 |language=en-US}}</ref>