Appendix 3

AAN system for translation of evidence to recommendations
Translation of evidence to recommendationsRating of recommendations
Level A rating requires at least one convincing class I study or at least two consistent, convincing class II studiesA = Established as useful/ predictive or not useful/ predictive for the given condition in the specified population
Level B rating requires at least one convincing class II study or overwhelming class III evidenceB = Probably useful/ predictive or not useful/ predictive for the given condition in the specified population
Level C rating requires at least two convincing class III studiesC = Possibly useful/ predictive or not useful/ predictive for the given condition in the specified population
U = Data inadequate or conflicting. Given current knowledge, test, predictor is unproven