OBJECTIVE: The aim of this study was to compare data on both alcohol use and alcohol-related consequences between intensive longitudinal data collection and the retrospective Timeline Followback (TLFB) interview.
METHOD: Heavy drinking college students (n = 96; 52% women) completed daily reports across a 28-day period to assess alcohol use and positive and negative consequences of drinking. They returned to the lab at the end of this period to complete a TLFB assessing behavior over those same 28 days. First, t tests were used to compare variables aggregated across the full 28 days at the between-person level. Next, hierarchical linear modeling was used to examine within-person differences between methods for each variable in weekly and daily increments.
RESULTS: Many alcohol use and consequence variables were significantly different when derived from self-reports during TLFB versus daily reports. In contrast to prior work, we found that higher estimates of drinking were reported retrospectively on the TLFB than on the daily reports. In addition, discrepancies were greater on some variables for heavier drinkers and when more time had elapsed between the end of the daily reporting period and TLFB collection.
CONCLUSIONS: Recall of drinking behavior during TLFB and daily reports may differ in systematic ways, with discrepancies varying based on participant and methodological characteristics.