4.9 Motions Challenging Expert Testimony

• Library: Federal Civil Practice in Virginia (Virginia CLE) (2023 Ed.)

4.9 MOTIONS CHALLENGING EXPERT TESTIMONY

4.901 Daubertv. MerrellDow Pharmaceuticals,Inc.

¹²⁸² In Daubert, the United States Supreme Court established a two-prong test that must be met for scientific expert testimony to be admitted properly: (i) whether the reasoning or methodology underlying the testimony is scientifically valid and (ii) whether the reasoning or methodology properly can be applied to the facts in issue. ¹²⁸³

Fed. R. Evid. 702 has been amended in response to Daubert, setting forth a nonexclusive checklist for trial courts to use in assessing the reliability of scientific expert testimony:

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 Eastern District of Virginia has interpreted Daubert and Fed. R. Evid. 702 as imposing three requirements: (i) the proposed expert must be qualified to give an opinion on scientific, technical, or other "specialized knowledge" by either knowledge, skill, experience, training, or education; (ii) the reasoning or methodology underlying the proffered opinion must be reliable; and (iii) the application of the underlying reasoning or methodology must be relevant to the facts of the case. ¹²⁸⁴

In Daubert, the Supreme Court charged trial judges with the responsibility of acting as gatekeepers to exclude unreliable scientific expert testimony. ¹²⁸⁵ The Supreme Court recognized that Fed. R. Evid. 702 imposes a special obligation on the district court to "ensure that any and all scientific testimony . . . is not only relevant, but realistic." ¹²⁸⁶

The Fourth Circuit has stated that the district court

should be conscious of two guiding, and sometimes competing, principles. On the one hand, the court should be mindful that R ule 702 was intended to liberalize the introduction of relevant expert evidence. . . . On the other hand, the court must recognize that due to the difficulty of evaluating their testimony, expert witnesses have the potential to "be both powerful and quite misleading." ¹²⁸⁷

Courts must be mindful that experts have the potential to be misleading if their testimony is not reliable. Expert testimony with a greater potential to mislead than to aid the jury should be excluded. ¹²⁸⁸

4.902 Kumho Tire Co.v. Carmichael.

¹²⁸⁹ In Kumho, the United States Supreme Court held that Daubert's general holding—setting forth the district court's general "gatekeeping" obligation—applies not only to testimony based on "scientific" knowledge, but also to testimony based on "technical" and "other specialized" knowledge. ¹²⁹⁰

4.903 Procedure.

The Reference Manual on Scientific Evidence, published by the Federal Judicial Center, endorses hearings on motions in limine pursuant to Fed. R. Evid. 104(a) as the proper method for determining the relevance and admissibility of scientific evidence. ¹²⁹¹

Both the Eastern and Western Districts of Virginia have recognized a motion in limine as the proper method to challenge expert qualifications. ¹²⁹²

The issue can also be raised in a motion to strike a declaration in support of a motion for summary judgment under Fed. R. Civ. P. 56(e). ¹²⁹³

The party offering the expert testimony must come forward with evidence from which the court can determine that the proffered testimony is admissible. ¹²⁹⁴ "The proponent of the testimony must establish its admissibility by a preponderance of proof." ¹²⁹⁵

It may be necessary to conduct a "Daubert hearing" to determine whether to exclude proposed expert testimony. ¹²⁹⁶

Pursuant to Fed. R. Evid. 104(a), the district court is not bound by the Rules of Evidence in making a preliminary determination on the admissibility of scientific testimony. "Thus, in determining whether to admit scientific testimony the court may consider materials not admissible in evidence." ¹²⁹⁷

Daubert has no application to fact witnesses. ¹²⁹⁸

The admissibility of expert testimony in a federal court sitting in diversity is controlled by federal law, not state law. ¹²⁹⁹

4.904 Daubert/Kumho Analysis.

Daubert requires the district court first to analyze the method used by the proposed expert.

A. Step One—Analyzing the Expert's Theory or Technique.

The following five factors are to be considered. ¹³⁰⁰

1. Whether the theory or technique used by the expert can be, or has been, tested;

2. Whether the theory or technique used by the expert has been subjected to peer review and publication;

3. The known rate or potential rate of error of the method used;

4. The existence and maintenance of standards controlling the technique's operation; and

5. The degree of the method's or conclusion's acceptance within the relevant scientific community.

Although specifically delineated by the Supreme Court, the above factors do not constitute an exhaustive list and "the inquiry envisioned by Rule 702" remains "a flexible one" in which many factors may be relevant. ¹³⁰¹

Not all Daubert factors apply to every scientific expert witness, as some scientific claims may not have been subject to peer review, and the general acceptance factor has no application to disciplines that lack any reliability, "such as astrology or necromancy." ¹³⁰² Determining the reliability of an...