Comparison 10. Risk of bias subgroup analysis: blinding of placebo treatment providers.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Placebo intervention provider blinded: yes	19	2707	Risk Ratio (M‐H, Random, 95% CI)	0.97 [0.91, 1.05]
2 Placebo intervention provider blinded: no or not stated	25	3334	Risk Ratio (M‐H, Random, 95% CI)	0.90 [0.83, 0.99]
3 Placebo intervention provider blinded: yes	42	3069	Std. Mean Difference (IV, Random, 95% CI)	‐0.15 [‐0.27, ‐0.02]
4 Placebo intervention provider blinded: no or not stated	116	7444	Std. Mean Difference (IV, Random, 95% CI)	‐0.26 [‐0.32, ‐0.19]