What percentage of the time does the one leg stand test correctly predict if a subject has a BAC above 0.08?

The correct answer reflects the accuracy of the one leg stand test in predicting whether a subject has a blood alcohol concentration (BAC) above 0.08. Research indicates that the one leg stand test has been shown to correctly identify individuals with a BAC over the legal limit 83% of the time. This figure is based on empirical studies that test the effectiveness of field sobriety tests used by law enforcement to determine impaired driving due to alcohol.

The 83% accuracy rate means that when the test is administered properly, it provides reliable evidence of impairment, which is significant in law enforcement contexts. This level of predictive validity is particularly useful for officers as they assess drivers' impairment.

In contrast, the other percentages provided do not align with the established statistics for the one leg stand test’s validity in detecting higher BAC levels. While a higher percentage may suggest an even greater accuracy, it does not accurately reflect the results of research conducted on the test’s performance. The selection of 83% provides a realistic expectation of the test's usefulness in real-world applications and aligns with the findings that support its employment in DUI investigations.