Using cash rewards to incentivize drug users to remain sober:
"In some cases it may not be feasible to reinforce every instance of abstinence as indicated by biochemical measures, as in voucher-based methods, either for practical or financial reasons. Thus, Petry and colleagues (29) investigated an alternative method to deliver incentives that they termed the “fishbowl prize” method. In their initial study, participants withdrew a slip of paper from a bowl contingent on demonstrating abstinence. The bowl contained 250 slips of paper, each of which represented one of four possible outcomes: (a) 50 slips contained no prize, (b) 169 slips resulted in a low magnitude prize valued at approximately $1.00 (e.g., food coupons, toiletries, or bus tokens), (c) 17 slips contained a medium prize valued at approximately $20.00 (e.g., CDs, phone cards), and (d) 1 slip contained a large prize valued at approximately $100.00(e.g., stereo, DVD, television). Using this fishbowl method, participants achieved significantly higher levels of alcohol abstinence, relative to standard care alcohol treatment."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3311913/
"In some cases it may not be feasible to reinforce every instance of abstinence as indicated by biochemical measures, as in voucher-based methods, either for practical or financial reasons. Thus, Petry and colleagues (29) investigated an alternative method to deliver incentives that they termed the “fishbowl prize” method. In their initial study, participants withdrew a slip of paper from a bowl contingent on demonstrating abstinence. The bowl contained 250 slips of paper, each of which represented one of four possible outcomes: (a) 50 slips contained no prize, (b) 169 slips resulted in a low magnitude prize valued at approximately $1.00 (e.g., food coupons, toiletries, or bus tokens), (c) 17 slips contained a medium prize valued at approximately $20.00 (e.g., CDs, phone cards), and (d) 1 slip contained a large prize valued at approximately $100.00(e.g., stereo, DVD, television). Using this fishbowl method, participants achieved significantly higher levels of alcohol abstinence, relative to standard care alcohol treatment."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3311913/