A comparison of two retrospective measures of weekly alcohol consumption: diary and quantity/frequency index.

There is currently uncertainty regarding the relative performance of a retrospective diary (RD) and a quantity-frequency index (QFI) measure of weekly alcohol consumption. While some previous studies have found more consumption reported on an RD than a QFI, others have found the reverse. As yet, however, no study has compared computerized versions of these two measures. This cross-sectional study involved administration of a computerized survey in a community-based drug and alcohol treatment setting. Five hundred and eighty-six clients (420 males) attending counselling for a range of drug- and alcohol-related issues agreed to participate in the study. The major finding was that more alcohol consumption was reported on the RD, than on the QFI. Similarly, the RD detected a greater proportion of both heavy and high-risk drinkers than the QFI. It is argued that the RD may be preferable to the QFI as a measure of weekly alcohol consumption, for use in community-based treatment settings.