The Accuracy of Standardized Field Sobriety Testing (SFST) with Dr. Greg Kane

The accuracy reported by SFST validation studies don't account for the false positives and the lack of control groups in the studies.

I interview Dr. Greg Kane, a medical doctor and expert in the science of standardized field sobriety testing (SFST). Dr. Kane highlights some of the inaccuracies and flaws of SFSTs.

He discusses the origins of SFST, the problems with validation studies, and the misleading nature of reported accuracy. Dr. Kane also explains the impact of control groups on test validity and dives into the accuracy of sobriety tests.

Despite the shortcomings of SFST, Dr. Kane expresses skepticism about the possibility of changing the system.

Key Takeaways:

  • Standardized field sobriety tests (SFST) were developed in the 1970s and have been used by law enforcement agencies to determine alcohol impairment. However, the science behind these tests is flawed and lacks proper validation.

  • Validation studies for SFST often fail to include control groups, leading to misleading accuracy claims. The reported accuracy of 91% is based on officers' ability to predict blood alcohol levels, not the accuracy of the tests themselves.

  • The accuracy of SFST is significantly lower when control groups are taken into account. For example, the walk-and-turn test is only 15% accurate when considering the control group.

  • Recent studies have also shown that SFST for THC (the psychoactive component of cannabis) have low accuracy rates, further questioning the reliability of these tests.

  • Despite the flaws and inaccuracies of SFST, it is unlikely that the system will change due to the legal and institutional barriers.

Notable Quotes:

  • "The numbers they report in court come from the San Diego study that did not use control groups. They're misleading because they grossly overstate the diagnostic performance of the test by ignoring the control group." - Dr. Greg Kane

  • "The bottom line is the numbers they report in court, the 91 percent, that's not even the accuracy of the sobriety test. It's the accuracy of police officers estimating the driver's blood alcohol level [after using a PBT]." - Dr. Greg Kane


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