The Kane Study: Why DRE Evidence in Georgia DUI Cases May Not Be as Reliable as Prosecutors Claim
If you’ve been arrested for DUI in Cobb County or anywhere in Georgia and a Drug Recognition Expert (DRE) evaluated you, you may have been told that the officer’s opinion is scientifically validated. But a 2013 critical review of the foundational studies supporting the DRE protocol raises serious questions about its reliability in court.
What Is a Drug Recognition Expert (DRE)?
A DRE is a police officer specially trained to evaluate drivers suspected of drug impairment. The DRE protocol involves a 12-step process that includes:
Breath alcohol test
Interview of the arresting officer
Preliminary examination
Eye examinations (including HGN)
Divided attention tests
Vital signs check
Dark room examinations
Muscle tone check
Injection site inspection
Suspect statements
Opinion formation
Toxicological sample
The DRE then forms an opinion on whether the driver was impaired by a specific category of drug (or combination of drugs).
Prosecutors often present DRE testimony as strong evidence of impairment, even when blood or urine results are pending or inconclusive.
The Kane Study: A Critical Look at the Science Behind DRE
Kane examined the three studies most frequently cited by law enforcement and prosecutors to support the accuracy of the DRE protocol:
Bigelow et al. (1985) – laboratory study
Compton (1986) – field study
Adler et al. (1994) – field study
These studies are referenced in the IACP DRE training manual and are often used in court to argue that DRE opinions are scientifically reliable.
Kane’s conclusion was clear: These studies contain serious methodological flaws that distort their reported accuracy rates. They do not properly validate the DRE protocol as it is currently used in real-world policing.
Key Problems Identified in the Kane Study
Kane used the QUADAS tool (a standard method for assessing diagnostic accuracy studies) and found multiple biases in all three studies, including:
Spectrum bias — The studies used highly selected groups (either healthy volunteers given high drug doses or only arrested drivers already suspected of impairment). This does not reflect typical DUI stops.
Selection bias — Officers were often allowed to choose which suspects to include, skewing results.
Verification bias — Toxicology testing was frequently performed only on suspects the DRE believed were impaired, not on everyone evaluated.
Misclassification and circular reasoning — The studies often used toxicology results to “confirm” impairment rather than independently measuring actual driving impairment or functional deficits.
Lack of reproducibility — The exact procedures used in the studies (especially the full DRE evaluation including circumstantial evidence and officer questioning) were not clearly standardized or described for replication.
Prevalence-dependent statistics — High accuracy numbers (often 83–94%) were heavily influenced by the high percentage of drug-positive subjects in the study samples. These numbers do not translate well to real-world DUI cases where drug prevalence varies widely.
Kane noted that the studies could not properly calculate sensitivity and specificity due to these flaws, and the reported accuracies are not generalizable to current DRE practice.
What This Means for Your Georgia DUI Case
Georgia courts allow DRE testimony in DUI cases, but the weight given to that testimony can be challenged. The Kane study provides strong ammunition for defense attorneys to argue that:
The scientific foundation for DRE opinions is weaker than prosecutors suggest.
DRE conclusions often rely on subjective interpretation rather than objective, validated measurements.
Many DRE opinions are later contradicted by toxicology results (or lack thereof).
The protocol has significant room for error, especially with certain drug categories.
Experienced DUI lawyers routinely cross-examine DRE officers on the limitations of their training and the studies used to support it. When the foundational research contains major methodological problems, the officer’s opinion becomes much less persuasive to judges and juries.
The Kane study does not claim that all DRE evaluations are wrong. It does show that the primary studies prosecutors rely on to claim the protocol is scientifically validated have serious flaws. This creates important opportunities to challenge DRE evidence in Cobb County and throughout Georgia.
If you were arrested for DUI and a DRE officer evaluated you — especially if drugs were alleged — the scientific weaknesses identified in the Kane study could be critical to your defense.
Contact George C. Creal Jr., P.C. today for a free consultation. With decades of experience handling complex DUI cases involving DRE testimony in Cobb County and Metro Atlanta, we know how to effectively challenge questionable scientific evidence and fight for the best possible outcome.
Call 404-333-0706 or visit www.georgecreal.com to speak with an experienced Georgia DUI defense attorney.
This article is for informational purposes only and does not constitute legal advice. Every case is different. Results depend on the specific facts of your case.
