Comparison 2. MI in addition to other SC treatment versus that SC treatment alone.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 All studies: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
2 Intensity subgroups: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
2.1 Intervention higher intensity	11	3838	Risk Ratio (M‐H, Random, 95% CI)	1.01 [0.76, 1.35]
2.2 Intensity matched	1	329	Risk Ratio (M‐H, Random, 95% CI)	1.30 [1.06, 1.59]
3 Provider subgroups: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
3.1 Physician	1	55	Risk Ratio (M‐H, Random, 95% CI)	0.77 [0.23, 2.57]
3.2 Nurse	2	298	Risk Ratio (M‐H, Random, 95% CI)	0.52 [0.09, 2.95]
3.3 Counsellor	8	3405	Risk Ratio (M‐H, Random, 95% CI)	1.08 [0.89, 1.32]
3.4 Lay healthcare worker	1	409	Risk Ratio (M‐H, Random, 95% CI)	2.30 [1.40, 3.81]
4 Counselling modality subgroups: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
4.1 Some face‐to‐face	8	2818	Risk Ratio (M‐H, Random, 95% CI)	1.17 [0.87, 1.56]
4.2 No face‐to‐face	4	1349	Risk Ratio (M‐H, Random, 95% CI)	0.86 [0.53, 1.42]
5 Fidelity subgroups: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
5.1 Fidelity monitoring reported	5	2115	Risk Ratio (M‐H, Random, 95% CI)	0.90 [0.57, 1.41]
5.2 No fidelity monitoring reported	7	2052	Risk Ratio (M‐H, Random, 95% CI)	1.20 [0.93, 1.56]
6 Baseline motivation subgroups: cessation	12	4167	Risk Ratio (M‐H, Random, 95% CI)	1.07 [0.85, 1.36]
6.1 Motivated	3	855	Risk Ratio (M‐H, Random, 95% CI)	1.30 [1.10, 1.54]
6.2 Not selected on motivation	8	2854	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.69, 1.55]
6.3 Not motivated	1	458	Risk Ratio (M‐H, Random, 95% CI)	0.70 [0.36, 1.37]