Table. 1.

Qualitative modified approach to grading of evidence

Level I Strong Evidence obtained from multiple relevant high-quality randomized controlled trials for effectiveness
or
Evidence obtained from multiple relevant high quality observational studies or large case series for assessment of preventive measures, adverse consequences, and effectiveness of other measures.
Level II Moderate Evidence obtained from at least one relevant high-quality randomized controlled trial or multiple relevant moderate or low-quality randomized controlled trials
or
Evidence obtained from at least 2 high-quality relevant observational studies or large case series for assessment of preventive measures, adverse consequences, and effectiveness of other measures.
Level III Fair Evidence obtained from at least one relevant high-quality nonrandomized trial or observational study with multiple moderate or low-quality observational studies
or
At least one high-quality relevant observational studies or large case series for assessment of preventive measures, adverse consequences, and effectiveness of other measures.
Level IV Limited Evidence obtained from multiple moderate or low-quality relevant observational studies
or
Evidence obtained from moderate quality observational studies or large case series for assessment of preventive measures, adverse consequences, and effectiveness of other measures.
Level V Consensus based Opinion or consensus of large group of clinicians and/or scientists for effectiveness as well as to assess preventive measures, adverse consequences, and effectiveness of other measures.

Adapted from the article of Manchikanti et al. (Pain Physician 2014; 17: E319-25) [30].

Korean J Pain 2021;34:346~368 https://doi.org/10.3344/kjp.2021.34.3.346
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