The use of electronic debit cards in longitudinal data collection with geographically mobile drug users

To assess the use of electronic debit (ATM) cards in conducting longitudinal research with geographically mobile ("urban nomad") drug users.: Young illicit drug users with recent travel history were street-recruited from the Lower East Side area of New York City. Multiple efforts were made to develop positive relationships between participants and the study. Honoraria were paid through electronic debit cards usable at ATMs countrywide. Participants were encouraged to complete follow-up interviews in person if they were in New York, or by telephone if elsewhere. Follow-up rates from two other recent cohort studies of young drug users in New York are used to illustrate use of the electronic debit card method.: One hundred and thirty-nine participants were recruited during 2001-2002. They had traveled extensively, averaging 31 trips per participant to different cities during the previous 3 years. Telephone follow-up interviews were obtained from participants in over 200 different cities/towns. Follow-up interview rates were 81% at 6 months and 71% at 12 months - substantially higher than corresponding rates in the comparison studies.: The use of electronic debit cards, combined with other efforts to develop positive relationships with participants, led to high rates of continued study participation. Debit cards may be very useful in conducting longitudinal research with geographically mobile populations.