J Can Chiropr Assoc 2026 (Apr); 70 (1): 27-54

Appendix 10. Certainty of evidence for intervention--
Efficacy of SMT parameters for Neck pain

Outcomes No. of participants randomized (Studies) Parameter Results favor (SMT, null, parameter) Risk of Bias (low, acceptable, high) Certainty of the evidence Comments (Reasons for downgrade/ upgrade)
Pain Intensity

Scale: 11-Point box pain scale		 182 (1 RCTs) 12 weeks SMT vs 36 weeks SMT 1 favors 36 weeks 1 low risk ⊕⊕○○
Low		 Imprecision
Neck-Specific Disability Status

Scale: NDI		 182 (1 RCTs) 12 weeks SMT vs 36 weeks SMT 1 favors null 1 low risk ⊕⊕○○
Low		 Imprecision
Functional Status

Scale: SPPB		 182 (1 RCTs) 12 weeks SMT vs 36 weeks SMT 1 favors 36 weeks 1 low risk ⊕⊕○○
Low		 Imprecision
Quality of Life/ Activities of daily living

Scale: EQ		 182 (1 RCTs) 12 weeks SMT vs 36 weeks SMT 1 favors null 1 low risk ⊕⊕○○
Low		 Imprecision

Abbreviations:

NDI = Neck Disability Index;
RCT = randomized controlled trial;
SMT = spinal manipulative therapy:
SPPB = short physical performance battery;
EQ = EuroQol EQ-5D