State v. Romero (2016)
The Arizona Supreme Court Rules that the Scientific Method is a Proper Subject for Expert Testimony and Cross-Examination
First Jury Trial. The government’s firearm expert testified and concluded the casings at the scene matched the gun found near Romero. However, a mistrial resulted.
The scientific method is a fundamental process. It uses logical steps to answer questions. It is only by properly following every step, that is required in a specific circumstance, can you determine if something is the product science or not?
Skip a necessary step – and your results – cannot be relied on.
Failure to properly conduct a necessary step – and your results – cannot be relied on.
At the hearing, Romero presented the testimony of an expert in the requirements of fundamental scientific methods. Romero’s expert, Dr. Haber, at the hearing:
- Stated the general features of conventional toolmark comparison testing that fell short of scientific standards for experimental design.
- He further testified that those failings limited the scientific weight that could be placed on the results of any such test.
- Opined that the tests, even if conducted correctly, could not scientifically justify the conclusions that the government sought to draw.
Dr. Haber was not offered to:
- Comment on the facts of the case
- To opine whether Powell was “right or wrong.”
The trial denied Romero’s motion to preclude the government’s expert’s testimony. However, the court went a step further. At the same it granted the government’s motion to preclude Dr. Haber from testifying as a defense expert at the jury trial.
The Second Trial. Romero was acquitted of first-degree murder. However, he was convicted of second-degree murder.
Arizona Court of Appeals
Arizona Court of Appeals. The Court of Appeals affirmed the conviction. See State v. Romero, 236 Ariz. 451, ¶¶ 18-32 457-60 (App. 2014)). A majority of the court of appeals’ panel affirmed the conviction and the exclusion of Romero’s expert’s testimony.
Arizona Supreme Court
The Scope of Review
The court agreed to review only the trial court court’s ruling regarding the preclusion of Dr. Haber’s testimony at trial. The Court did not review the denial of Romero’s Daubert challenge regarding the government’s expert.
The Court frames the issue as whether Romero’s expert was qualified in field that he was offer for at trial – experimental deign.
The Purpose Dr. Haber's Testimony
Dr. Haber’s testimony served more than one purpose. While the trial did not find it persuasive enough to grant Romero’s Rule 702 Motion – Romero also sought to use it to persuade the jury.
The Court correctly stated why Romero was calling Dr. Haber at his jury trial: “the methods generally used in conventional toolmark analysis fall short of scientific standards for experimental design.”
The purpose of Dr. Haber’s testimony went to “the scientific weight” the jury should (or should not) give the government’s expert testimony.
Qualified for His Purpose
Dr. Haber was an expert in the field of experimental design. Put another way, he was an expert regarding the fundamental requirements of the scientific method.
The Arizona Supreme Court found: “[w]ith respect to experimental design, and a comparison of the methods generally used by firearms examiners to the scientific method, Dr. Haber is qualified as an expert.”
Helpful to the Jury
Rule 702 requires that expert testimony be “helpful” to the jury in understanding the evidence. Ariz. R. Evid. 702(a).
The purpose of the government’s expert’s testimony was to match the shell casings to the gun. The bases of this conclusion were “toolmark comparisons.” The government’s expert quantified his match opinion was to “a reasonable degree of scientific certainty.”
Accordingly, the Supreme Court found “Dr. Haber’s testimony would have been helpful to the jury in understanding how the toolmark analysis differed from general scientific methods and in evaluating the accuracy of Powell’s conclusions regarding ‘scientific certainty.’”
The court also explained how the testimony could be helpful:
Not a Second Daubert Hearing
The Supreme Court determined that the “trial court’s alternative ground for preclusion was an error of law.”
- The trial court’s reasoning “fail[ed] to recognize that very often the same proof used to establish admissibility also impacts weight and credibility.”
- Blanket preclusion at trial of evidence presented at a pretrial hearing “infringe[s] upon the role of the jury and improperly insulate[s] the state’s evidence from critique.”
The trial court’s alternative ground for preclusion was determined to be an error of law.
In the End...
The Supreme Court “vacate paragraphs 19 through 32 of the opinion of the court of appeals.” It also remanded the case to the court to determine if the exclusion Dr. Haber’s testimony was “harmless.”