Implications for practice 

• There is high‐certainty evidence that incentives boost long‐term cessation rates (six months or more) in mixed‐population studies. This effect appears to persist following their discontinuation, suggesting that even a short incentivised intervention may have long‐term benefits.
• There is moderate‐certainty evidence that incentives also boost the long‐term cessation rates of pregnant women who smoke, which continues post‐partum. 
• Low‐ to moderate‐value incentives appear to achieve sustained success rates beyond the end of the reward schedule, suggesting that even modest incentive schemes may be effective at encouraging long‐term smoking abstinence. 
• Deposit‐refund trials may be prone to low rates of uptake compared to reward‐based programmes; however, people who do sign up and contribute their own money achieve comparable or higher quit rates than reward‐only participants. 
• Although concern has been expressed about incentive‐based interventions attracting smokers motivated more by the material rewards than by the desire to quit, there was little evidence that levels of deception varied between experimental and control participants, or that rates of disconfirmation were unacceptably high. The motivation for entering an incentive‐based cessation scheme may be less important than eventual engagement in promoting smoking cessation.

Implications for research 

• Evaluation of different incentive reward schedules for smoking cessation is needed. 
• Further large, well‐conducted trials are needed on the effectiveness of using incentives for smoking cessation in low‐ and middle‐income countries and in pregnant women. 
• Trials are needed that directly compare high‐ and low‐value incentives to assess whether there is a difference in effect. A possible approach would be to evaluate incentive value as a percentage of mean study participant income. 
• The affordability and cost effectiveness of incentive programmes should be tested in real‐world settings, as part of the evaluation process. 
• Implementation and acceptability of incentives in real‐world settings should be formally evaluated, including directly comparing or assessing the value of incentives alongside other smoking cessation interventions. 
• Trials in pregnant women should explore the effect of financial versus deposit‐based incentives. 
• Potential disbenefits and harms of incentives interventions require monitoring in future trials. 

[Clinical staff may also be interested in the clinical answers related to this review https://www.cochranelibrary.com/cca/doi/10.1002/cca.2669/full and https://www.cochranelibrary.com/cca/doi/10.1002/cca.2670/full]