Kadden 2007.

Methods	RCT (dismantling design).
Participants	240 adult marijuana smokers meeting DSM‐IV criteria for cannabis dependence. USA.
Interventions	9 weeks of one of four conditions: 1. case management control condition (n= 62) 2. MET/CBT coping skills training (n= 61) 3. contingency management (n= 54) 4. MET/CBT + Contingency management (n= 63).
Outcomes	Physiological primary: None. Non‐physiological primary: Total 90‐day continuous abstinence. Proportion of days abstinent. Secondary: Readiness to change (Readiness to Change Questionnaire). Follow‐up was at 2 months posttreatment.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computerized urn randomisation.
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement.
Blinding (performance bias and detection bias) Patients and providers	Unclear risk	No blinding but the outcome measurements are not likely to be influenced by lack of blinding due to validation with physiological measurement.
Blinding (performance bias and detection bias) Assessors	Unclear risk	Insufficient information to tell if assessor was blinded, but the outcome measurements are not likely to be influenced by lack of blinding due to validation with physiological measurement.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	17% lost to follow‐up with reasons stated. Different attrition across groups. No ITT.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the study purposes.
Other bias	Low risk	Urine samples were collected to check on self‐report. There were no differences between groups at baseline. No additional sources of bias appear to be present.