Schwartz 2006.

Methods	Two group randomised controlled trial with participants randomised to interim methadone maintenance treatment or a wait list control. Random assignment generated by random number table and sealed in an envelope.
Participants	Geographic region: USA Study setting: community methadone treatment facility. n=319, 59% male mean age =41.4 years 93% African American 62% unemployed Eligibility criteria; DSM IV heroin dependence and informed consent. Exclusions; pregnant or acute medical or psychiatric illness.
Interventions	Treatment: interim methadone maintenance treatment for 120 days after which entry into a comprehensive methadone treatment program if unable to gain entry before 120 days. Control: wait‐list
Outcomes	Entry into comprehensive methadone maintenance treatment at 4 months. Illicit drug use /self report and urinalysis. Criminal activity.
Notes	Mobile program that at time of study administered methadone from specially equipped recreational vehicle
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	'table of random numbers'
Allocation concealment?	Unclear risk	B ‐ Unclear. Sealed envelope but unclear if opaque and sequentially numbered.
Incomplete outcome data addressed? All outcomes	Low risk	Missing outcome information balanced between groups. 95% MMT and 89% wait list located for follow up.
Free of other bias?	Low risk	No difference between group at baseline