Alessi 2014.

Methods	Country: USA Setting: residential substance use disorder clinics, southern Connecticut Design: randomized controlled trial
Participants	45 participants (24 Intervention, 21 Control). All were men aged 18+, smoking 10+ cpd with interest in quitting smoking, who were entering long‐term (> 6 months) residential substance use disorder treatment. Average age 37; 84% “non‐Hispanic”; average 11.4 years education; average 18.6 cpd at baseline with groups similar at baseline.
Interventions	All participants received 2 quit‐smoking preparation sessions, the first consisting of CO measurement, 30‐minutes counselling and a self‐help quit guide, with a review of progress and a quit date set in the second session 4 days later. All participants received US$15 at intake, US$25 per follow‐up and a US$1 gift certificate/snacks/gum for each CO and cotinine sample, irrespective of smoking status. 1. Control: additionally received a brief monitoring intervention consisting of 5‐minute individualized support/feedback Monday‐Friday for 4 weeks. CO measured and cpd tracked at each session. Cotinine measured weekly. 2. Intervention: received the control intervention plus entry into multiple prize draws, contingent on abstinence, as follows: Week 1: a “guaranteed prize” bowl with 70 cards, of which 64 had a US$1 prize (e.g. toiletries, sports drink, gum), 5 for a US$20 prize (e.g. exercise weights, portable games, Barnes and Noble gift cards), and 1 for a US$100 prize (linens, TV, and DVD player), with 1 to 5 draws available depending on number of consecutive CO tests abstinent. Weeks 2 to 4: a “standard prize” bowl with 500 cards, 50% of which had a prize (219 US$1 prizes, 30 US$20 prizes and 1 US$100 prize). A cotinine‐negative test gave 5 bonus draws. Overall, 190 draws were available for negative CO tests (mean earnings US$426.56) and 15 for negative cotinine tests (mean earnings US$46.43).
Outcomes	7‐day PPA at 4, 8, 12, 24 weeks, biochemically verified twice‐daily by CO (< 6 ppm) and weekly by urinary cotinine (< 30 ng/mL) % reduction in cpd, self‐efficacy, non‐nicotine substance use
Notes	Also in ISC.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “Randomization to one of two conditions occurred using an urn procedure.”
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical verification used.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Very few losses; 2 participants left the treatment centre before completion.