Longitudinal substance abuse research has often been compromised by high rates of attrition, thought to be the result of the lifestyle that often accompanies addiction. Several studies have used a standardized follow-up protocol to minimize attrition, however it is unclear whether this protocol is equally effective for participants struggling with varying levels of housing stability, support for sobriety, and substance abuse severity. The current study extends research supporting the effectiveness of this protocol by demonstrating the importance of two central aspects of the follow-up protocol: locator form completion and continual verification contacts. Results indicated that each additional piece of locator form information and verification contact significantly and independently increased the odds for completing a follow-up interview, and that these effects were not moderated by participant characteristics. Practical and theoretical implications for longitudinal substance abuse research are discussed.