Alcohol abuse screening instruments: normative test data collected from a first DWI offender screening program.

Objective: A variety of instruments are used by Driving While Impaired (DWI) screening programs nationwide to assess offenders for alcohol- or drug-related problems. This study presents normative data from five standardized instruments administered by a DWI screening program: the MAC scale of the MMPI, the Alcohol Use Inventory (AUI), the Michigan Alcoholism Screening Test (MAST), the Drug Abuse Screening Test (DAST) and the Skinner's Trauma Scale (STS).

Method: The population under study were 2,317 first DWI offenders who completed screening evaluations in 1989-91. The sample included 24% women; the racial distribution was 46% Hispanic, 43% non-Hispanic white, 8% Native American and 3% other races. A statistical model was developed to determine associations among scores on the various instruments and age, gender, ethnicity, education, blood alcohol concentration (BAC) and validity measures on the MMPI-2 (L and K scale scores)

Results: There were significant differences in test scores among the ethnic- and gender-specific client groups. Test scores were significantly higher among men than women for the MAST, the D1 and D2 scales of the AUI, the MAC, and the STS. Correlations among the instruments were generally low, and the percentage of persons who scored above instrument cut-points varied significantly. The MAST identified the highest percentage of persons as alcoholic. MMPI profile validity was the most significant independent variable associated with test scores. Persons with scores in the valid range had higher mean scores on each of the instruments.

Conclusions: The choice of instruments used in the DWI assessment can greatly influence the percentage of offenders assessed as having alcohol-related problems.