Tracy 2007.

Methods	Allocation: randomised. Design: single‐centre. Duration: 1 month. Setting: community. Location: New Haven Connecticut, USA.
Participants	Diagnosis: Met current or lifetime DSM‐IV Axis 1 psychiatric disorder* and had a co‐occurring current diagnosis of cocaine or alcohol abuse or dependence. N = 30. Age: not stated. Sex: gender not stated. Inclusion criteria: homeless or seeking shelter at least 18 years of age in addition to current SUD and psychiatric diagnosis.
Interventions	1. Psychosocial intervention: Contingency management: Low‐cost contingency management with variable ratio reinforcement where patients received reinforcers** contingent upon demonstrating abstinence from both alcohol and cocaine, as verified by breathalyser and cocaine‐free urine specimens. N = 15. 2. Standard care: TAU, assessment only. N = 15.
Outcomes	Leaving the study early: lost to treatment (4 weeks). Unable to use Substance use: mean and SDs not provided for alcohol and substance use; percentages (and Chi2 statistics) are provided for some outcomes but not subject number (N) for each group.
Notes	* Specific diagnoses are not reported, unknown seriousness or duration of psychiatric illness. ** Reinforcers were redeemable prizes ranging in value from no prize, $1, $20 and $100. All participants received $30 for the screening, baseline and termination interviews and $5 for each weekly assessment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised using a table. No further details.
Allocation concealment (selection bias)	Unclear risk	No details provided.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Clinician‐/participant‐mediated and participants and personnel not blinded. It is not possible to blind a psychosocial intervention.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated if raters were blind to allocation.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Lost to follow‐up: 13% (4/30) 1 month. Four patients in the TAU (assessment only) group did not complete the study, no further details are provided. Analyses adjusted for greater cocaine use using covariate.
Selective reporting (reporting bias)	High risk	Gender, specific diagnoses and age not reported for participants. Mean and SDs not provided for alcohol and substance use; percentages (and Chi2 statistics) are provided for some outcomes but not participant number (N) for each group.
Other bias	Low risk	No evidence other biases are occurring.

F = Female, M = Male, N = Number
 ITT ‐ Intention‐to‐treat analysis

LOCF ‐ Last observation carried forward

RDC ‐ Research diagnostic criteria
 SCID ‐ Structured Clinical Interview for Diagnosis

Type of care
 AA ‐ Alcoholics Anonymous
 ACT ‐ Assertive Community Treatment
 CBT ‐ Cognitive Behaviour Therapy
 NA ‐ Narcotics Anonymous

For full list of diagnostic scales and abbreviations see Table 10.