Test–retest reliability of an online measure of past week alcohol consumption (the TOT-AL), and comparison with face-to-face interview

ObjectiveThis paper reports on the development of a new online measure of beverage-specific past week alcohol consumption (the TOT-AL), its test–retest reliability, and comparability with the face-to-face approach of ascertaining alcohol intake.MethodsUniversity students participating in the reliability study completed the TOT-AL twice on the same day with at least 3 h apart. Students in the comparability study attended a face-to-face interview and completed the TOT-AL on the same day, in a randomised order, at least 3 h apart.ResultsThere was a strong correlation between the repeated measurements of the TOT-AL (r = 0.99; 95% CI: 0.98, 0.99) and between the units calculated by the TOT-AL and the face-to face interview (r = 0.97; 95% CI: 0.95, 0.99). A high level of agreement between measurements was also observed in a Bland–Altman analysis.ConclusionsThe TOT-AL is a reliable, time efficient means of ascertaining alcohol intake, equivalent to that obtained face-to-face. These findings support the use of this approach to online alcohol assessment in populations with access to the Internet.