Cataloging blood alcohol level and alcohol consumption data in field settings: feasibility and findings.

A team of two female interviewers, two male interview assistants, and one or two additional male observers were stationed in front of targeted drinking establishments to survey individuals about their drinking practices and to collect blood alcohol levels (BALs) using portable breath testers. Of the 176 individuals asked to participate, 156 (88%) consented to be interviewed and 141 (90%) provided breath samples. Of those tested, 40 (29%) were legally intoxicated (BAL greater than or equal to 100 mg/dl) while 68 (49%) registered a BAL of 50 mg/dl or greater. The mean BAL was 72 mg/dl. Individuals reporting that they were going to drive had significantly lower BALs than those planning not to drive. Subjects who thought they were legally intoxicated, on average, had BALs greater than the legal level of intoxication, and BALs significantly greater than those who felt they were not intoxicated. These data suggest that the collection of BAL, in combination with self-reported alcohol data, is an important component of methodologically sound alcohol field research.