Two Brief Measures of Alcohol Use Produce Different Results: AUDIT-C and Quick Drinking Screen.

BACKGROUND: Several psychometrically sound measures of alcohol use have been developed to assess drinking. The Alcohol Use Disorders Identification Test (AUDIT) and its shorter counterpart the AUDIT-C, which contains the first 3 AUDIT questions, were developed by the World Health Organization and have become the preferred brief measures for screening and evaluating problem severity. This study compared the first 3 questions on the AUDIT with another psychometrically sound brief measure of alcohol use, the Quick Drinking Screen (QDS).

METHODS: Data were obtained from a randomized controlled trial of a mail-based intervention promoting self-change with 472 alcohol abusers (n = 280, no prior alcohol treatment; n = 192, prior alcohol treatment). Participants' retrospective self-reports of alcohol consumption were collected using the QDS and the 3 AUDIT-C questions and compared. Although both measures contain similar questions (2 quantity-frequency and 1 binge drinking), they differ in 2 important ways: (i) temporal interval over which data are collected, and (ii) formatting of response options (i.e., a continuous number vs. categorical).

RESULTS: Intraclass correlations for drinking variables were moderate to moderately high. A repeated-measures MANOVA using treatment condition and gender as variables revealed significant differences in absolute values between the 2 drinking measures with the QDS showing greater consumption on almost all variables. Participants' numerical answers on the QDS were compared to their categorical answers to the similar alcohol use questions on the AUDIT-C. The comparison revealed that participants' answers on the AUDIT-C were associated with extreme variability compared to their QDS answers. This variability suggests the AUDIT-C would be unreliable as a quantitative measure of alcohol consumption.

CONCLUSIONS: The differences between the 3 alcohol use questions on the AUDIT-C and the same questions on the QDS may reflect the imprecision of the AUDIT-C's drinking response categories. Results suggest that the QDS can be used to identify risky drinking and to provide a more informative characterization of a drinker's alcohol consumption than that provided by the AUDIT-C.