TABLE 1

Grading the Body of Evidence13

GradeMethodDescription
HighSufficient number of high-quality studies with consistent resultsFurther research is unlikely to change our confidence in the answer to the clinical question.
ModerateA single well-performed study, or multiple studies of lesser quality or with some uncertaintyFurther research is likely to have an important impact on our confidence in the precision of the answer to the clinical question and may even change the answer itself.
LowStudies with insufficient quality including case reports, case studies, general reviews, and local consensusThere is published and/or local consensus, but little or no research, to answer the clinical question. Further research is likely to have an important impact on the answer.
Grade not assignableInsufficient design or execution, too few studies, inconsistent results, and lack of consensusThere is insufficient evidence and lack of consensus to answer the clinical question.