Objective: Retrospective self-reports of alcohol consumption are ubiquitous in the alcohol research field. Time frames of these reports range from a week to a year or longer and are subject to several influences of bias that may have important clinical, epidemiological and methodological consequences. In order to specify drinking patterns more precisely, a study was conducted to monitor alcohol consumption on a daily basis. Method: Subjects (N = 51) responded for 112 days on an Interactive Voice Response system by entering their data daily using the touch-tone pad of their telephone. Each day, subjects answered 11 questions relating to drinking (including quantity) and to variables believed to affect consumption (e.g., stress level). Results: The overall response rate was 93.0%. Subjects reported consuming at least one drink on 51.2% of all 5,151 reporting days (mean number of drinks reported = 4.6). Following completion of the study, subjects were also asked to recall consumption retrospectively using a standard quantity-frequency questionnaire. Conclusions: The present study demonstrated that: (1) data can be collected on a daily basis efficiently, and (2) traditional methods of data collection (e.g., quantity-frequency) result in a significant underreporting bias for heavier drinkers.
