In 2012, Arizona courts incorporated federal rule of evidence 702, which codified the United Supreme Court's Daubert decision. The current Arizona Rule 702 reads:
A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: a) the expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert has reliably applied the principles and methods to the facts of the case.
The Daubert standard is completely different from the previous Arizona Frye standard, which strictly focused if the technique used was "generally accepted in the scientific community". Under Daubert the Supreme Court defined "scientific methodology" as the process of formulating hypotheses and then conducting experiments to prove or falsify the hypothesis and enumerated criteria for establishing the "validity" of scientific testimony:
1. Empirical testing: whether the theory or technique is falsifiable, refutable, and/or testable.
2. Whether it has been subjected to peer review and publication.
3. The known or potential error rate.
4. The existence and maintenance of standards and controls concerning its operation.
5. The degree to which the theory and technique is generally accepted by a relevant scientific community. (Daubert v. Merrell Dow Pharmaceuticals, Inc.
While Arizona Courts have previously admitted field sobriety tests and horizontal gaze nystagmus tests under the Frye standard, the Arizona Supreme Court has not ruled on this issue under the new Daubert standard.
Other courts, however, have addressed this issue. In U.S. v. Horn,:
Thus, based on the foregoing, I conclude that the SFST evidence in this case does not, at this time, meet the requirements of Daubert/Kumho Tire and Rule 702 as to be admissible as direct evidence of intoxication or impairment.
The Montana Supreme Court concluded a trial court abused its discretion in admitting HGN results even though the government proved the officer was qualified to administer the test and conducted it as instructed:
This testimony shows that Officer Kennedy was trained to administer the HGN test and, in fact, administered the HGN test on Hulse in accordance with this training, and, therefore, he was qualified to testify as to both his administration of the HGN test and his evaluation of Hulse's performance.
However, nothing in the evidence establishes that Officer Kennedy had special training or education nor adequate knowledge qualifying him as an expert to explain the correlation between alcohol consumption and nystagmus, the underlying scientific basis of the HGN test.
Accordingly, we conclude there was insufficient foundation for the admission of evidence concerning the HGN test and the District Court abused its discretion when it summarily denied Hulse's motion in limine and allowed Officer Kennedy to testify as to Hulse's HGN test results.
A Connecticut Court of Appeals ruled the same way:
We conclude, therefore, that the court abused its discretion in admitting Kovanda's testimony regarding the results of the defendant's HGN test without requiring that the state satisfy the criteria for the admission of scientific evidence as set forth in Daubert.(State v. Russo)
Finally, in the most extensive analysis of this issue, the New Mexico Supreme Court held the results of the HGN should not have been admitted in a DUI trial.
We also hold that testimony as to the results of a Horizontal Gaze Nystagmus (HGN) test should not have been admitted at trial, because the State failed to lay a proper foundation for the admission of this expert testimony. Although the State qualified a police officer as an expert in administering the test, it failed to show the evidentiary reliability of HGN testing. (State v. Torres)
The New Mexico Supreme Court noted that Arizona courts had admitted HGN results under the Frye standard:
Unlike New Mexico, the Arizona courts have rejected Daubert in favor of the "general acceptance" standard articulated in Frye, 293 F. at 1014. See State v. Tankersley, 191 Ariz. 359, 956 P.2d 486, 491 (1998). Given that HGN testimony had been ruled admissible in Arizona courts four years prior to City Court, see State v. Superior Court, 149 Ariz. 269, 718 P.2d 171, 181 (1986) (en banc) we do not find it surprising that the prosecution met the "general acceptance" standard in that case without any additional testimony regarding the scientific principles upon which the HGN test is based.
But under the New Mexico Daubert standard, that evidence is not admissible:
Although the State presented evidence at trial as to Officer Bowdich's training and experience with HGN testing, we conclude that his training and experience are not sufficiently probative of the test's evidentiary reliability...
As stated previously, Arizona no longer uses the Frye standard and any evidence must meet the Daubert standard. In other words, while the results of field sobriety tests have been admitted in Arizona DUI cases for ages, maybe that will soon change...