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

Appendix 9. Certainty of evidence for intervention --
Efficacy of SMT vs comparator for Neck pain

Outcomes No. of participants randomized (Studies) Results favor (SMT, null, comparator) Risk of Bias (low, acceptable, high) Certainty of the evidence Comments
Pain Intensity

Scale: 11-Point box scale		 241(1 RCT) 1 favors SMT 1 low risk ⊕⊕○○
Low		 Imprecision
Neck-Specific Disability Status

Scale: NDI		 241 (1 RCTs) 1 favors null 1 low risk ⊕⊕○○
Low		 Imprecision
Functional Status

Scale: SF-36 physical function subscale		 241 (1 RCTs) 1 favors null 1 low risk ⊕⊕○○
Low		 Imprecision
Quality of Life/ Activities of daily living No trials were identified that reported on this outcome. ⊕○○○
Very Low		 No Relevant Studies

Abbreviations:

NDI = Neck Disability Index;
RCT = randomized controlled trial;
SF = short form,
SMT = spinal manipulative therapy