Comparison 1. Flexible‐dose buprenorphine versus flexible‐dose methadone.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Retention in treatment	11	1391	Risk Ratio (M‐H, Random, 95% CI)	0.83 [0.73, 0.95]
1.1 Double‐blind flexible dose studies	5	788	Risk Ratio (M‐H, Random, 95% CI)	0.83 [0.72, 0.95]
1.2 Open label flexible dose studies	6	603	Risk Ratio (M‐H, Random, 95% CI)	0.80 [0.63, 1.02]
2 Morphine‐positive urines	8	1027	Std. Mean Difference (IV, Random, 95% CI)	‐0.11 [‐0.23, 0.02]
3 Self‐reported heroin use	4	501	Std. Mean Difference (IV, Random, 95% CI)	‐0.11 [‐0.28, 0.07]
4 Cocaine‐positive urines	6	919	Std. Mean Difference (IV, Random, 95% CI)	0.10 [‐0.05, 0.25]
5 Benzodiazepine‐positive urines	6	859	Std. Mean Difference (IV, Random, 95% CI)	0.05 [‐0.12, 0.22]
6 Criminal activity	2	328	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.10 [‐0.31, 0.12]