Expert witness testimony is governed by the New Mexico Rules of Evidence, Article 7 (Opinions and Expert Testimony). In particular, Rule 11-702 states:

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 thereto in the form of an opinion or otherwise.

The New Mexico Supreme Court ruled in State v. Alberico, 116 N.M.156 (1993), that the admission of expert testimony is no longer governed by the so-called “Frye Test,” which had allowed scientific evidence only if it had acquired “general acceptance” in the scientific community. Instead, the court held that the testimony of an expert is admissible under Rule 702 of the New Mexico Rules of Evidence if the following three elements are satisfied:

1. The expert is qualified.
2. The expert testimony will assist the trier of fact.
3. The expert testifies only to scientific, technical or other specialized knowledge.

The witness must be qualified as an expert.
Ordinarily the party calling an expert witness will begin by asking about the witness’s qualifications. This might include the witness’s educational background, such as degrees, advanced study and research. It might include teaching and publications. The expert might also testify about any honors or awards he or she has received. Experts often describe their experience in their profession as well as any previous expert testimony they may have given in other cases.

At this point, many lawyers tender the witness as an expert, saying something like:

“Your Honor, I offer Dr. _____ as an expert witness.”

If there is any objection at this point, the court will determine whether the witness has sufficient qualifications to testify as an expert. Sometimes the opponent will request leave to conduct a voir dire examination of the witness in an attempt to undermine his or her qualifications.

Ultimately, it is for the court to decide whether the witness will be permitted to testify.

2. The expert testimony must be helpful to the trier of fact, i.e. the judge or jury.
Most experts are called to the stand because they are able to offer insights and explanations of the significance of the evidence that lay jurors would be unable to make on their own. The proponent of the witness can’t simply dress up in scientific terms what the fact finder could determine through common sense.

The trial judge has discretion to permit the expert witness to testify if the judge determines that the testimony would be helpful.

3. The testimony must relate to a scientific, technical or other specialized subject.
This requirement may be difficult to assess: just what, exactly, is science?

What is Science?
Shortly after the New Mexico Supreme Court decided Alberico, the United States Supreme Court took a similar position in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). In Daubert, the Supreme Court abandoned the old “general acceptance” rule and ruled that the Federal Rules of Evidence were designed to liberalize the admission of scientific evidence. The court stated that a trial judge faced with a proffer of expert testimony must make “a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts in issue.” 590 U.S. at 592-593.

Although Daubert interpreted Rule 702 of the Federal Rules of Evidence, New Mexico’s Rule 702 is identical. Thus, Daubert’s discussion of how to determine whether an expert’s testimony is “ground[ed] in the methods and procedures of science” can be helpful to New Mexico courts.

Daubert says that “[scientific knowledge] represents a process for proposing and refining theoretical explanations about the world that are subject to further testing and refinement.” 509 U.S. at 590. Although the Supreme Court declined to establish a rigid test or procedure for determining whether an expert’s testimony is “grounded in science,” it discussed four basic considerations that should be met:

1. Has the scientific knowledge been tested?
2. Has the theory or technique been subjected to peer review and publication?
3. Is there any known or potential rate of error?
4. Has the scientific knowledge gained general acceptance in the relevant scientific community?

None of these suggested criteria is an absolute requirement to a ruling that an expert may testify, but the party offering the evidence would be well-advised to lay a foundation that at least approximates these standards.

The Daubert court emphasized that the court’s assessment under Rule 702 is flexible. “Its overarching subject is the scientific validity -- and thus the evidentiary relevance and reliability -- of the principles that underlie a proposed submission. The focus, of course, must be solely on principles and methodology, not on the conclusions that they generate.” 590 U.S. at 594-595.