How is the reliability of the SFST assessed?

The reliability of the Standardized Field Sobriety Test (SFST) is primarily assessed through research and studies that validate its effectiveness in detecting impairment. Numerous studies have been conducted to ensure that the tests used in the SFST—such as the Horizontal Gaze Nystagmus, Walk-and-Turn, and One-Leg Stand—have proven to be accurate indicators of alcohol and drug impairment. These studies evaluate how well the tests perform under various conditions and the degree to which they correlate with blood alcohol content levels or other measures of impairment.

This scientific validation process includes controlled experiments and field studies conducted in varied environments, which help establish a standardized approach to administering and interpreting the tests. When thoroughly validated, these tests can significantly aid law enforcement in making informed decisions during roadside assessments for suspected impaired drivers.

Research-based validation is crucial because it provides empirical evidence that forms the foundation for training law enforcement personnel, ensuring that the procedures are grounded in science rather than subjective observations. This enhances the credibility and reliability of the SFST in judicial settings, reinforcing its acceptance as a reliable method for determining impairment.