Do research payments precipitate drug use or coerce participation?

Providing high-magnitude cash incentives to substance abuse clients to participate in research is frequently viewed as unethical based on the concerns that this might precipitate new drug use or be perceived as coercive. We randomly assigned consenting drug abuse outpatients to receive payments of 10 US dollars, 40 US dollars, or 70 US dollars in either cash or gift certificate for attending a 6-month research follow-up assessment. At the 6-month follow-up, participants received their randomly determined incentive and were then scheduled for a second follow-up appointment 3 days later to detect new instances of drug use.