Statistics

  • Level of Evidence
  • Grades of Recommendation

Level of Evidence

LevelDescription
1High-quality prospective randomized clinical trial
2Prospective comparative study
3Retrospective case control study
4Case Series
5Expert Opinion

Grades of Recommendation

GradeDescription
ATreatment options are supported by strong evidence (consistent with Level I or II studies)
BTreatment options are supported by fair evidence (consistent with Level III or IV studies)
CTreatment options are supported by either conflicting or poor quality evidence (Level IV studies)
IWhen insufficient evidence exists to make a recommendation
given to various treatment options based on Level of Evidence supporting that treatment