Effectiveness of monetary incentives for recruiting adolescents to an intervention trial to reduce smoking

The study objective is to evaluate the effect of monetary incentives on response rates of adolescents to a smoking-related survey as the first step toward participation in an intervention trial.

A sample of 4,200 adolescent members of a managed care organization were randomized to one of four incentive groups: a $2 cash group, a $15 cash group, a $200 prize drawing group, or a no-incentive group. We compared group-specific response rates and willingness to be contacted about future study activities, as well as costs.

Incentives increased survey response rates (55% response without incentive vs. a 69% response with incentive), with response of 74% in the $15 cash group, 69% in the token group, and 63% with a prize incentive. Incentives did not adversely affect willingness of adolescents to be contacted about a smoking intervention, (65% willing with incentives vs. 60% without, P = 0.03). In terms of cost per additional survey completed, token and prize groups were marginally more expensive than the no-incentive group ($0.40 and $1.42, respectively) while the large cash incentive was substantially more costly ($11.37).

Monetary incentives improve response rates to a mailed survey, without adverse impact on willingness to further participate in intervention activities. However, a variety of issues must be considered when using incentives for recruitment to intervention studies.