Validation of a multisubstance online Timeline Followback assessment

OBJECTIVES: The Timeline Followback (TLFB) was originally developed to assess alcohol consumption patterns (American Journal of Public Health, 86, 1996, 966) and has been increasingly modified for Web‐based use. Additionally, new modes of substance use administration have emerged, creating a need for an adaptable TLFB tool than can capture data such as cannabis product potency or prescription drug use. Our goal was to validate an online TLFB that reliably assesses a wide range of substances in greater detail. METHODS: Using a within‐subjects counterbalanced design, daily substance use data were collected from 50 college students over a 14‐day retrospective period using both the traditional in‐person TLFB and online TLFB (O‐TLFB). RESULTS: All substance use variables, including detailed measures of cannabis metrics, correlated significantly (r's ranged from .653 to .944, p < .001) between TLFB versions. Further, results demonstrated that both the online TLFB and in‐person TLFB demonstrated concurrent validity with both the Alcohol Use Disorders Identification Test (AUDIT) and Marijuana Dependence Scale (MDS). CONCLUSION: Overall, the data suggest that this new O‐TLFB demonstrates strong reliability and delivers a versatile and secure tool for substance use assessment that is relevant to a variety of biomedical and psychological research contexts.