Date of Award


Degree Name

Doctor of Philosophy


Counselor Education and Counseling Psychology


The present study set out to investigate the reliability and performance of the BAC DataMaster®, an infrared-based alcohol breath testing instrument. The focus of this study was to determine: (a) the impact of varying breath sample duration during testing, (b) if Blood Alcohol Concentration (BAC) levels produced by the DataMaster® (BACDM) are significantly different from BAC levels produced by analysis of whole blood (BACWB), and (c) if the relationship between BACDM estimates and BACWB is influenced by the amount of alcohol an examinee has ingested. Each of 27 participants was randomly assigned to one of three alcohol intake groups: high intake BAC = 10g/210ml; medium intake BAC = 08g/210ml; or low alcohol intake BAC = 06g/210ml. Participants ingested 100 proof vodka in six drinks spaced at ten-minute intervals. Total alcohol intake was 2.36 ml of alcohol per 1 kg of body weight (high intake), 2.00 mi per 1 kg of body weight (medium intake), or 1.64 ml of alcohol per 1 kg of body weight (low intake). After alcohol ingestion and a 1-hour, 15-minute absorption period, participants provided the researcher with blood and breath samples. Six breath samples were collected from each participant; two breaths under each of the follow breath duration conditions: Condition 1-short duration exhale, (SDE); Condition 2—medium duration exhale, (MDE); and Condition 3—long duration exhale, (LDE). Pre- and post-breath testing blood samples were analyzed at a local laboratory and BACWB results were compared to BACDM estimates. Two major findings emerged from this research. First, significant differences were found to exist between BACDM estimates and BACWB results, specifically, BACDM estimates underestimated BACWB results. Second, BACDM estimates are significantly affected by the duration of breath samples. In general, BACDM estimates computed from SDE breath samples are lower then BACDM estimates computed from LDE breath samples. This effect was seen across all alcohol intake groups, but was most significant in the high alcohol intake group. The practical and theoretical implications of these findings are discussed and recommendations for improving testing procedures are offered.

Access Setting

Dissertation-Open Access