“…Monetary rewards have been shown to be the most effective in this type of research (e.g., Benishek et al, 2014 ; Davis et al, 2016 ). Reinforcement or incentives, in the form of monetary vouchers, has been successful in increasing the probability of enrollment in treatment for opiate abuse (e.g., Holtyn et al, 2021 ), promoting abstinence from alcohol (e.g., Koffarnus, DeFulio et al, 2021 ), cocaine (e.g., Silverman et al, 1996 ), opiates (e.g., Robles et al, 2002 ), and other applications (e.g., polydrug abuse, injection substance users).…”