Participants
Participants were recruited from 4 methadone clinic programs in Baltimore, Maryland, between March 2015 and September 2019 using self and counselor referrals. Eligible participants were aged 18 years or older, were enrolled in methadone treatment, self-reported using cocaine 1 day or more in the past 30 days, provided a urine sample testing positive for cocaine at screening or in the past 3-month clinical record, and met 