Expert Opinion
The opinion of economic experts can be useful and relevant in a number of ways including a determination of domestic industry, patent validity, damages, disgorgement of profits and equitable remedies. The admissibility of expert testimony is subject to rule 402 of the Federal Rules of Evidence, which stipulates that all evidence must be relevant.
All relevant evidence is admissible, except as otherwise provided by the Constitution of the United States, by Act of Congress, by these rules, or by other rules prescribed by the Supreme Court pursuant to statutory authority. Evidence which is not relevant is not admissible.
— Federal Rules of Evidence, Article IV, Rule 402.
Evidence is relevant if it tends to shine a light on facts that are of consequence to a determination.
Relevant evidence is defined as that which has any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence. Rule 401.
— Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 US 579, 587 (S.Ct. 1993).
Experts have more latitude than other witnesses in offering opinion to the court.
Unlike an ordinary witness, see Rule 701, an expert is permitted wide latitude to offer opinions, including those that are not based on firsthand knowledge or observation.
— Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 US 579, 587 (S.Ct. 1993).
Rule 702 sets forth the rules with regard to expert testimony and defines what it means to be an expert.
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.
— Federal Rules of Evidence, Article VII, Rule 702.
Notably, expert testimony must be both relevant and reliable. Opinion must be more than mere speculation.
The adjective scientific implies a grounding in the methods and procedures of science. Similarly, the word knowledge connotes more than subjective belief or unsupported speculation. … Of course, it would be unreasonable to conclude that the subject of scientific testimony must be known to a certainty; arguably, there are no certainties in science.
— Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 US 579, 590 (S.Ct. 1993).
The Supreme Court provided considerations that are relevant to the determination of reliability in Daubert v. Merrell Dow Pharmaceuticals, Inc.
[W]hether it can be (and has been) tested[;] … whether the theory or technique has been subjected to peer review and publication[;] … [and] the known or potential rate of error[.] … [G]eneral acceptance can yet have a bearing on the inquiry.
— Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 US 579, 594 (S.Ct. 1993).
Opinions on patent damages need not be free of uncertainty but must employ a reliable methodology.
All approximations involve some degree of uncertainty, the admissibility inquiry centers on whether the methodology employed is reliable.
— Summit 6, LLC v. Samsung Electronics Co., Ltd., 802 F. 3d 1283, 1298 (Fed. Cir. 2015).
Critically, both data and methodology must be sufficiently tied to the facts of the case.
A distinct but integral part of that inquiry is whether the data utilized in the methodology is sufficiently tied to the facts of the case. Kumho Tire, 526 U.S. at 150, 119 S.Ct. 1167. Hence, a reasonable or scientifically valid methodology is nonetheless unreliable where the data used is not sufficiently tied to the facts of the case.
— Summit 6, LLC v. Samsung Electronics Co., Ltd., 802 F. 3d 1283, 1298 (Fed. Cir. 2015).
The Court of Appeals for the Federal Circuit has clamped down in recent years on this point. I provide a number of examples in subsequent chapters.