TRACKING SUBSTANCE-ABUSERS IN LONGITUDINAL RESEARCH - UNDERSTANDING FOLLOW-UP CONTACT DIFFICULTY

Studies examining follow-up contact difficulty provide useful informat ion for planning longitudinal studies and for assessing the validity o f follow-up data. Contact difficulty was examined among 96 substance a busers following substance abuse treatment. Interview completion rates at the 3-month and 6-month follow-ups were 93 and 97%, respectively. The extent of contact efforts required to complete follow-up interview s varied substantially but tended to be greater at the 3-month follow- up than at the 6-month followup. Contact difficulty was related to reu se of substances at the 3-month and at the 6-month follow-lips with re users requiring greater contact efforts than abstainers. None of the b aseline individual and contextual variables examined significantly pre dicted level of contact effort at follow-ups. Attrition-related validi ty implications are discussed along with practical suggestions for pla nning tracking efforts.