A large study in the New England Journal of Medicine verifies that financial rewards for quitting smoking are effective. Participants were randomly offered one of a variety of incentive schemes that paid participants who successfully quit smoking (verified with saliva and urine tests). Participants were free to decline the offer.
The most interesting variation of the study was to compare a carrot model which paid up to $800 for success with a carrot-stick model in which participants lost $150 if they failed to stop smoking but gained $800 if they succeeded (i.e. $650 of reward plus refund of $150). In theory, the carrot-stick model should work better because it harnesses loss-aversion. And statistical analysis suggested that for those who would accept either the carrot or the carrot-stick model, the carrot-stick model did work better. The problem is that far fewer people who were offered the carrot-stick model chose it compared to those offered the carrot model. Overall, therefore, the carrot model was far more successful.
Smokers are costly so even a pure carrot model of $800 paid by employers would more than pay for itself:
…Finally, the finding that individual rewards of $800, as compared with usual care, nearly tripled the rate of smoking cessation among CVS Caremark employees and their friends and family confirms and extends the generalizability of our finding from a previous trial involving General Electric employees. In addition to the public health effects of such smoking reductions, these findings are important for employers. Because employing a smoker is estimated to cost $5,816 more each year than employing a nonsmoker, even an $800 payment borne entirely by employers and paid only to those who quit would be highly cost-saving.