A comparison between two retrospective alcohol consumption measures and the daily drinking diary method with university students

Background: There are two main categories of retrospective self-report alcohol consumption measures: summary and daily drinking. Time-efficient summary measures have been criticized for being less able to capture sporadic and unpatterned drinking. A novel retrospective summary measure, the Typical and Atypical Drinking Diary (TADD), may produce more precise estimates of alcohol consumption than the gold-standard daily measure, the Timeline Followback (TLFB). Objective: To establish how accurately the TADD and TLFB retrospectively capture alcohol consumption compared to the Daily Drinking Diary (DDD) method. Method: Forty-three university undergraduates (77% female) concurrently recorded their daily alcohol consumption for 28 consecutive days using daily drinking diaries. Participants then retrospectively estimated their alcohol consumption using both the TADD and TLFB 28 days following completion of the 28-day daily consumption period. Results: When compared against the drinking data obtained from the DDD method, the TADD consistently produced accurate retrospective estimates of total alcohol consumption, number of drinking days, and number of heavy drinking episodes. Contrariwise, the TLFB significantly underestimated all aspects of drinking. Underreporting on the TLFB was hypothesized to be associated with social desirability bias. Conclusion: The TADD is a valid and reliable instrument for retrospectively measuring alcohol consumption and drinking variability in the university student population.