What Is the Daubert Standard and Why Does It Matter for DUI Cases?

The Daubert standard for evaluation of expert witness testimony becomes very important in DUI defenses based on scientific evidence. Use of scientific experts is on the rise in DUI defense, but more than half the battle is getting an expert before the court in the first place. When prosecutors try to exclude an expert witness’s testimony, the trial court uses the Daubert standard (as adopted by Oklahoma) to decide whether to allow it into court.

The Daubert standard comes from a Supreme Court case, Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). In the case, the court created a new test to evaluate scientific expert witness testimony that replaced the formerly used Frye standard. The Frye standard, still used in some states, requires a judge to determine whether the method by which scientific evidence was obtained was generally accepted by experts in that scientific field. The Daubert standard is more complicated: the judge assesses whether an expert’s testimony is based on reasoning or a method that is scientifically valid and can properly be applied to the facts at issue. The judge acts as a “gatekeeper” in evaluating the relevance and reliability of expert testimony. To be relevant, the testimony must assist the trier of fact (the jury in a jury trial). Reliability is a more difficult question, and judges use five factors to evaluate it.

The five factors a judge may use in evaluating the reliability of expert testimony are:

• Whether the theory or technique in question can be and has been tested,
• Whether it has been subjected to peer review and publication,
• Its known or potential error rate,
• The existence and maintenance of standards controlling its operation, and
• Whether it has attracted widespread acceptance within a relevant scientific community.

Oklahoma courts use the Daubert standard, as enacted by case law and state statute. 12 O.S. § 12-2702 reads:

“If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education may testify in the form of an opinion or otherwise, if:

1. The testimony is based upon sufficient facts or data;
2. The testimony is the product of reliable principles and methods; and
3. The witness has applied the principles and methods reliably to the facts of the case.”

12 O.S. § 12-2702.

As you can see, the statute does not match up exactly with the Daubert standard as described above. However, the Oklahoma courts do use the Daubert standard, as declared in Taylor v. State, 1995 OK CR 10, 889 P.2d 319. Like federal courts, Oklahoma applies the Daubert standard to all specialized and technical knowledge (not just scientific knowledge), and to civil cases. Roberts v. State, 2000 OK CR 14, 8 P.3d 883; Christian v. Gray, 2003 OK 10, 65 P.3d 591.

Need an attorney for DUI charges in Oklahoma? Seek out the attorney who is in court nearly every day and teaches other attorneys and law enforcement about sobriety testing techniques. Clint Patterson, Esq., of Patterson Law Firm, a former Tulsa prosecutor now using his trial experience and expert-level knowledge of DUI science to defend drivers, has the experience and the insight to evaluate the strengths and weaknesses of your case. To schedule a case evaluation, visit Patterson Law Firm online or call Clint’s office at (918) 550-9175.