Evaluation of Combined Financial Incentives and Deposit Contract Intervention for Smoking Cessation: A Randomized Controlled Trial

Introduction. We evaluate whether a combination of financial incentives and deposit contracts improves cessation rates among low- to moderate-income smokers. Methods. We randomly assigned 311 smokers covered by Medicaid at 12 health clinics in Connecticut to usual care or one of the three treatment arms. Each treatment arm received financial incentives for two months and either (i) nothing further ("incentives only"), (ii) the option to start a deposit contract with incentive earnings after the incentives ended ("commitment"), or (iii) the option to precommit any earned incentives into a deposit contract starting after the incentives ended ("precommitment"). Smoking cessation was confirmed biochemically at two, six, and twelve months. Results. At two, six, and twelve months after baseline, our estimated treatment effects on cessation are positive but imprecise, with confidence intervals containing effect sizes estimated by prior studies of financial incentives alone and deposit contracts alone. At two months, the odds ratio for quitting was 1.4 in the incentive-only condition (95% CI: 0.5 to 3.5), 2.0 for incentives followed by commitment (95% CI: 0.6 to 6.1), and 1.9 for incentives and precommitment (95% CI: 0.7 to 5.3). Conclusions. A combined incentive and deposit contract program for Medicaid enrollees, with incentives offering up to $300 for smoking cessation and use of support services, produced a positive but imprecisely estimated effect on biochemically verified cessation relative to usual care and with no detectable difference in cessation rates between the different treatment arms.