Table 3.

Design features of studies included in the meta-analysis and assessment of their study quality.

Study	CM condition	Drugs Treated	Abstinence and Attendance	Prize or Voucher	Escalation (reset)	Frequencya	Reinforcer Magnitudeb	Treatment Duration (in weeks)	Overall Study Quality
Alessi et al. (2007)	CM + IOP	P	ABS + ATT	Prize	Yes (yes)	5	N/A	12	-
Carroll et al. (2006)	CM + MET, CBT CM + drug counseling	M	ABS + ATT ABS + ATT	Voucher Voucher	Yes (yes) Yes (yes)	1 1	$880 $880	8 8	-
Carroll et al. (2012)	CM + CBT	M	ATT	Prize	Yes (yes)	1	$250	12	+
Chen et al. (2013)	CM + methadone	O	ABS + ATT	Prize	Yes (yes)	1	$42	12	-
Jones et al. (2001)	CM + methadone	P	ABS + ATT	Voucher	Yes (no)	7	$525	2	+
Kidorf et al. (2013)	CM + case management	P	ATT	Voucher	No	7	$300	12	+
Marlowe et al. (2008)	CM + drug court CM + drug court	P	ATT ATT	Voucher Voucher	Yes (no) No	0.2 0.2	$390 $390	56 56	-
Petry et al. (2011)	CM + IOP	P	ABS + ATT	Prize	Yes (yes)	5	N/A	12	+
Petry et al. (2012)	CM + IOP	S	ATT	Prize	Yes (yes)	5	$250	12	+
Petry et al. (2018)	CM + MET, CBT, TSF	S	ATT	Prize	Yes (yes)	2	$190	12	+

Notes. All studies immediately reinforced attendance. + = high study quality (defined as studies meeting three or more indicators of low bias per the Cochrane Risk of Bias tool); - = low study quality (defined as studies meeting two or fewer indicators of low bias per the Cochrane Risk of Bias tool); ABS + ATT = CM protocol reinforced abstinence and attendance simultaneously; ATT = CM protocol reinforced attendance alone; CBT = cognitive-behavioral therapy; CM = contingency management; IOP = intensive outpatient treatment; M = marijuana; MET = motivational enhancement therapy; N/A = cannot be determined; O = opioids; P = polysubstance use; S = stimulants; TSF = twelve step facilitation;

^aRefers to the available number of times reinforcement was earned per week

^bRefers to the average maximum value that participants could earn during the CM protocol