A within-subjects validation of a group-administered timeline followback for alcohol use.

Abstract

Objective: The current study uses a within-subjects randomized design with the Timeline Followback (TLFB) method administered in groups or to individuals to determine the equivalence of these methods.

Method: One hundred and four male and female college students who reported drinking at least once in the past 3 months completed the TLFB during a one-on-one interview, as well as in a group setting days apart. The two administrations were counterbalanced among the participants. Drinking variables assessed were drinking days, average drinks, total drinks, and maximum drinks consumed both during a 3-month (90 days) and a 1-month (30 days) period.

Results: Repeated measures analyses revealed no differences within subjects between the individual TLFB and the group TLFB on any of the four assessed drinking variables in the past 3 months and the past 1 month. Pearson's correlation coefficients revealed strong and significant correlations between the two administration styles. Heavy episodic drinking behavior was similar across administration styles as well. No differences between administration styles were consistent regardless of which administration was received first.

Conclusions: The study suggests that the group TLFB yields similarly accurate results to the previously validated individual TLFB. The group-administered TLFB could be used in clinical and research settings as an efficient means of collecting information from large numbers of individuals.