Prior research has shown that providing higher cash payments increased follow-up rates in a treatment-outcome study without influencing participants’ perceptions of coercion or their relapse into drug use. Our study examined whether research participants were more likely to recall higher cash incentives after six months, and whether this would elicit more productive or efficient follow-up efforts. We randomly assigned consenting participants in outpatient drug abuse treatment to receive one of three payments ($10, $40, or $70) in either cash or gift certificates for attending a six-month follow-up research appointment. Results revealed that participants were more likely to remember incentives that were larger and paid in cash over a six-month period, and that participants offered larger incentives were much easier to contact.

Key words/concepts: participant remuneration, payments, incentives, follow-up