Level I | Strong | 2 or more relevant high quality RCT”s for effectiveness, or 4 or more relevant high quality observational studies of large case series for assessment of preventive measures, adverse, consequences, and effectiveness of the other measures |
Level II | Moderate | At least 1 relevant high quality RCT or multiple relevant moderate or low quality RCT”s or at least 2high quality relevant observational studies or large case series for assessment of preventive measures, adverse, consequences, and effectiveness of the other measures |
Level III | Fair | At least 1 relevant high quality nonrandomized trial or observational study with multiple moderate or low quality observational studies, or at least on high quality relevant observational study or large case series for assessment of preventive measures, adverse, consequences, and effectiveness of the other measures |
Level IV | Limited | Multiple moderate or low quality relevant observational studies, or moderate quality observational studies of large case series for assessment of preventive measures, adverse, consequences, and effectiveness of the other measures |
Level V | Consensus Based | Opinion or consensus of large group of clinicians for effectiveness as well as to assess preventive measures, adverse, consequences, and effectiveness of the other measures |