18.17.1 Who Is an Expert?

• Jurisdiction: Arizona

18.17.1 Who Is an Expert? The Arizona Rules of Evidence control who can be an expert witness.²⁵⁶ Rule of Evidence 702 was amended in 2012 and adopted Federal Rule of Evidence 702. The amendment recognizes that trial courts should serve as gatekeepers in assuring that proposed expert testimony is reliable and thus helpful to the jury’s determination of facts at issue.²⁵⁷ Although the comment to Rule 702 does not explicitly cite to Daubert v. Merrell Dow Pharmaceuticals,²⁵⁸ the comment acknowledges that the rule was amended to bring the rule in line with Federal Rule of Evidence 702.

Rule of Evidence 702 reads as follows:

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.²⁵⁹

The Supreme Court in Daubert set forth a list of non-exclusive factors in evaluating the reliability of expert testimony which include: “(1) whether the expert’s theory or technique can be or has been tested; (2) whether the theory or technique has been subjected to peer review and publication; (3) whether the technique or theory is generally accepted within the relevant scientific community; (4) the known or potential rate of error of the technique or theory when applied; and (5) the existence of and maintenance of standards controlling application of the technique.”²⁶⁰ Courts since Daubert have identified additional factors to be considered when determining reliability including whether: “(1) the expert’s testimony is prepared solely in anticipation of litigation, or is based on independent research; (2) the expert’s field of expertise/discipline is known to produce reliable results; (3) other courts have determined that the expert’s methodology is reliable; and (4) non-judicial uses for the expert’s methodology.”²⁶¹ Finally, courts have considered a number of factors when considering the reliability of an expert’s conclusions and opinions under Rule 702(d), including whether: “(1) the expert employs the same care as a litigation expert as he would in his regular professional work outside the courtroom; (2) the expert has accounted for obvious alternative explanations, and (3) the expert’s opinion adequately accounts for available data and unknown variables.”²⁶²

A trial court’s ruling that expert testimony is reliable does not necessarily mean that contradictory expert testimony is not reliable. The amendment is broad enough to permit testimony that is the product of competing principles or methods in the same field of experience. Where there is contradictory, but reliable, expert testimony, it is the province of the jury to determine the weight and credibility of the testimony.²⁶³

Interpreting Rule 702, the Arizona Supreme Court has developed a three-part test to determine the admissibility of expert opinion testimony based on human behavior.²⁶⁴ Expert opinion testimony on human behavior will be allowed when: (1) it is relevant to an issue in the case; (2) the testimony will aid in understanding evidence outside the experience or knowledge of the average juror; or (3) when the witness is qualified by “knowledge, skill, experience, training, or education.²⁶⁵

Educational attainments are not a prerequisite, and a person can be qualified as an expert by reason of experience alone.²⁶⁶ To be admissible, an expert’s opinion may rely upon facts from three types of sources: “(1) facts admitted into evidence at trial; (2) facts personally perceived by the expert; [or] (3) facts of a type reasonably relied upon by experts in the particular field.”²⁶⁷ The court of appeals held that “the test for admissibility of an expert’s opinion based on facts not in evidence is whether the source relied upon by the expert is reliable.”²⁶⁸

The Arizona Supreme Court has, at times, reduced the threshold question of admissibility even further. In Englehart v. Jeep, the court stated that the ultimate question as to admissibility will hinge on whether or not the proffered testimony would aid the jury.²⁶⁹ This is obviously a flexible standard, and whether or not it exists depends on the specific facts of the case. However, once the court rules that an expert’s testimony will, in fact, help the jury, only a showing of a clear abuse of discretion will necessitate a reversal by the appellate court.²⁷⁰

The court has thus decided to treat behavioral expert opinion testimony, including medical opinions, differently than expert opinions based upon the “hard” sciences.²⁷¹

Previously in Arizona, experts did not necessarily have to be familiar with the controlling standard of care in the disputed matter. In Perguson v. Tamis, the plaintiff’s expert witness, a board licensed OB/Gyn, testified that both the defendant doctor and his physician assistant (PA) were negligent.²⁷² This testimony was allowed even though the OB/Gyn admitted he was not “familiar with the law or standard of care applicable to PAs or their scope of practice in Arizona.”²⁷³ The court stated that because the relevant test is whether or not the witness possesses “special knowledge” that will help the jury in its deliberations, the testimony should be allowed.²⁷⁴

Because the expert possessed “years of experience, skill, knowledge, education and training” in the field of obstetrics, he was qualified to comment on the PA’s actions.²⁷⁵ Furthermore, the Arizona Supreme Court has previously held that an expert need not have the same schooling or training as the defending physician to be allowed to testify.²⁷⁶ “It is the scope of the witness’ knowledge and not the artificial classification by title that should govern the threshold question of admissibility.”²⁷⁷

Although there was no previous requirement that the expert witness be of the same specialty as the defending physician, evidence must be presented that establishes the similarities of the standards of care between the two fields.²⁷⁸ In most cases, this burden falls upon the expert witness.²⁷⁹ In Gaston, an orthopedic surgeon sought to testify as to the standard of care applicable to a neurosurgeon.²⁸⁰ However, he failed to establish that the “standards of care in the two specialties are the same or similar.”²⁸¹ As a result the expert’s testimony was disallowed.²⁸²

In Fridena v. Evans, the testifying expert was a medical physician and an orthopedic surgeon, whereas the defending physician was an osteopathic physician and an orthopedic surgeon.²⁸³ The court held that there had been no evidence presented as to any material differences between the two physicians’ schooling with respect to a particular condition that would render the expert unqualified.²⁸⁴

However, in Seisinger v. Siebel, the Arizona Supreme Court was faced with the issue of whether A.R.S. § 12-2604 conflicted with Arizona Rule of Evidence 702 regarding the requirements relative to expert witnesses.²⁸⁵ The underlying case involved a defendant anesthesiologist who administered a spinal epidural to plaintiff Laura Seisinger in 2002.²⁸⁶ Plaintiff filed a medical malpractice action against Dr. Siebel and disclosed that J. Antonio Aldrete, MD would testify as an expert against Dr. Siebel.²⁸⁷ Dr. Siebel filed a motion and argued that Dr. Aldrete, a...