Timeline Followback Self-Reports Underestimate Alcohol Use Prior to Successful Contingency Management Treatment

Aims: The timeline followback (TLFB) is a retrospective self-report task that has been used successfully to measure prior alcohol consumption. The current study reanalyzed data from a recent successful demonstration of a remote contingency management trial for reducing alcohol consumption. Methods: We first compared the accuracy of the TLFB and past-day self-reports to a biochemically verified measure of recent alcohol use (i.e., breathalyzer). We then compared the correspondence between the two self-report measures over two phases of the parent study: a phase immediately prior to and a phase including the treatment component. Results: Our findings indicated that past-day self-reports displayed significantly higher accuracy with breathalyzer measures as compared to TLFB. In addition, we found only the experimental group, after reducing consumption, reported lower alcohol use on the TLFB prior to the treatment compared to their past-day self-reports and to the control group. Conclusions: Our findings suggest daily monitoring techniques are more accurate than the TLFB for measuring alcohol consumption and when possible should be preferred over the TLFB. If the TLFB is the only viable method of measuring alcohol consumption, in order to maximize accuracy researchers and clinicians should obtain responses prior to the start of a procedure aimed at reducing alcohol consumption.