1a (Strong) :
Well-designed meta-analysis, or 2 or more high quality RCTs (PEDro ≥ 6) showing similar findings

1b(Moderate):
1 RCT of high quality (PEDro ≥ 6)

2a (Limited):
At least 1 fair quality RCT (PEDro = 4-5)

2b (Limited):
At least one poor quality RCT (PEDro < 4) or well-designed non-experimental study (non-randomized controlled trial, quasi-experimental studies, cohort studies with multiple baselines, single subject series with multiple baselines, etc.)

3 (Consensus):
Agreement by an expert panel or a group of professionals in the field or a number of pre-post studies all with similar results

4 (Conflicting):
Conflicting evidence of 2 or more equally well-designed studies

5 (No evidence):
No well-designed studies – only case studies/case descriptions or cohort studies/single subject series with no multiple baselines)