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. Author manuscript; available in PMC: 2022 Mar 5.
Published in final edited form as: Pain Physician. 2021 Mar;24(2):E131–E152.

Table 1.

Qualitative modified approach to grading of evidence.

Level I Strong Evidence obtained from multiple relevant high-quality RCTs
Level II Moderate Evidence obtained from at least one relevant high-quality RCT or multiple relevant moderate- or low-quality RCTs
Level III Fair Evidence obtained from at least one relevant moderate- or low-quality RCT with multiple relevant observational studies or
Evidence obtained from at least one relevant high-quality nonrandomized trial or observational study with multiple moderate- or low-quality observational studies
Level IV Limited Evidence obtained from multiple moderate- or low-quality relevant observational studies
Level V Consensus based Opinion or consensus of large group of clinicians and/or scientists

Adapted from Manchikanti L, Falco FJE, Benyamin RM, Kaye AD, Boswell MV, Hirsch JA. A modified approach to grading of evidence. Pain Physician 2014; 17:E319-E325 (6).