Expert testimony plays a critical role in intellectual property (IP) litigation, where questions about the scope of an IP owner's rights and whether those rights have been infringed often require a deep understanding of the underlying technology, market, or media. In these cases, parties frequently rely on expert witnesses to present scientific facts and opinions, while judges turn to experts to interpret technical evidence outside their own experience or knowledge. Unlike ordinary witnesses, expert witnesses are afforded "wide latitude to offer opinions, including those that are not based on firsthand knowledge or observation."1 Given this, it is important for IP litigators to ensure that experts present their testimony effectively and properly in front of the fact-finder, as the exclusion of an expert's testimony can devastate a party's case. This is particularly true in patent damages where the Federal Circuit has shown new interest in the standards for admitting expert testimony.
Judges Want Helpful Expert Testimony
Courts recognize their own limitations when addressing issues outside the legal domain. As the Federal Circuit has observed, "[c]ourts of law are not the optimal fora for trying questions of scientific truth; even less are appellate courts equipped to choose among conflicting scientific theories."2 The court further acknowledges that, in cases involving scientific matters, judges' decisions are "ultimately an educated guess" that is "dependent on the quality and strength of the scientific evidence brought before them."3
Nevertheless, judges are not required to accept any testimony from a self-proclaimed expert. In the landmark Daubert case, the U.S. Supreme Court, citing Federal Rule of Evidence 702, tasked trial judges with ensuring that any scientific testimony admitted is both relevant and reliable.4 The Court suggested several factors to evaluate the relevance and reliability of expert testimony, which have since been adopted into the amended Rule 702.
Rule 702: The Standard for Admitting Expert Testimony
Federal Rule of Evidence 702 allows an expert witness, qualified by "knowledge, skill, experience, training, or education," to testify and give opinions if the proponent can demonstrate to the court that "it is more likely than not that":
- 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;
- the testimony is based on suicient facts or data;
- the testimony is the product of reliable principles and methods; and
- the expert's opinion reflects a reliable application of the principles and methods to the facts of the case.5
Thus, the trial court acts as a "gatekeeper" to exclude expert testimony that is irrelevant or based on unreliable methodologies.6 Rule 702 provides requirements for assessing the reliability and helpfulness of proffered expert testimony.
Although the Advisory Committee Notes to the 2000 Amendments to Rule 702 clarified that the admissibility of all expert testimony is governed by the principles of Rule 104(a)-which requires the proponent to establish the admissibility of expert testimony by a preponderance of the evidence-the standard has been applied more leniently in some courts.7 The 2023 amendment to Rule 702 now explicitly requires that the proponent prove the admissibility of expert testimony by a preponderance of the evidence.8
Parties relying on (or challenging) expert testimony should understand these requirements.
The Expert Must Be Qualified
Under Rule 702, a witness who offers expert testimony must be "qualified as an expert by knowledge, skill, experience, training, or education."9 Courts have emphasized that, in patent cases-particularly those involving claim construction, validity, or infringement-a witness must at least have ordinary skill in the relevant art.10 However, no specific qualifications beyond ordinary skill in the art are required.11
Multiple degrees and academic appointments may bolster an expert's credibility, but if the requirements of Rule 702 are otherwise met, they are not required for admissibility.12 Furthermore, courts have declined to apply a timing requirement for expertise even when the expert gained their expertise after the time of the alleged invention.13
The Expert's Testimony Must Be Relevant and Based on Scientific, Technical, or Other Specialized Knowledge
The trial judge must determine whether the expert is offering testimony based on "(1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue."14
This requirement hinges on the intuitive question of whether a layperson could competently resolve the issue without the expert's specialized insight. As noted in the Advisory Committee Notes to the 1972 Proposed Rule 702, the key test is "whether the untrained layman would be qualified to determine intelligently and to the best possible degree the particular issue without enlightenment from those having a specialized understanding of the subject involved in the dispute."15 When expert opinions are excluded under this requirement, it is because they are deemed "unhelpful and . . . superfluous."16
The Expert's Testimony Must Be Reliable
Rule 702 includes three requirements to ensure the reliability of expert testimony: (1) it must be based on sufficient facts or data; (2) it must be the product of reliable principles and methods; and (3) it must reflect a reliable application of those principles and methods to the facts of the case. These factors align with, but are not a substitute for, the Daubert factors used to assess reliability.17
The Daubert factors include considerations such as "(1) whether the expert's technique or theory can be or has been tested-that is, whether the expert's theory can be challenged in some objective sense, or whether it is instead simply a subjective, conclusory approach that cannot reasonably be assessed for reliability; (2) whether the technique or theory has been subject to peer review and publication; (3) the known or potential rate of error of the technique or theory when applied; (4) the existence and maintenance of standards and controls; and (5) whether the technique or theory has been generally accepted in the scientific community."18 These factors are not exclusive or dispositive, and other factors may be considered, including whether the expert's testimony is based on independent research, whether the expert has accounted for alternative explanations, whether the expert is as careful as they would be in their regular professional work, and whether the field of expertise reliably produces valid results.19Ultimately, the trial judge must determine whether the reasoning and methodology underlying the testimony are scientifically valid and whether they can be properly applied to the case's facts.20
Recent Developments in the Application of Rule 702
The Federal Circuit recently granted rehearing en banc in EcoFactor, Inc. v. Google LLC, to address the application of Rule 702 to expert testimony on patent damages.21 In the original panel decision, the court upheld the District Court's admission of a damages expert's testimony, which relied on comparable license agreements.22 However, in a dissenting opinion, Judge Prost shared her views on flaws in the expert's methodology, including failure to properly apportion the value of the patented technology.23 The majority disagreed, arguing that if the admissibility standard were set too high, the trial judge would no longer act as a gatekeeper but would instead assume the role of the jury.24 The Federal Circuit's decision to rehear the case suggests that the court is evaluating the standard for admitting expert testimony on damages, particularly with regard to methodologies used to predict hypothetical negotiations and market reconstructions under the amended Rule 702's preponderance-of-the-evidence standard.
Conclusion
Here we can offer only a cursory review of Rule 702. Given the broad discretion granted to trial judges in deciding whether to admit expert testimony, parties should carefully review the requirements of the rules and relevant cases.
Footnotes
1 Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 592 (1993).
2 Zenith Laboratories, Inc. v. Bristol-Myers Squibb Co., 19 F.3d 1418, 1423 (Fed. Cir. 1994).
3 Id.
4 Daubert, 509 U.S. at 590 (1993).
5 Fed. R. Evid. 702.
6 Micro Chemical, Inc. v. Lextron, Inc., 317 F.3d 1387, 1391 (Fed. Cir. 2003).
7 Fed. R. Evid. 702, Advisory Committee Note to 2000 Amendments; David E. Bernstein, The Misbegotten Judicial Resistance to the Daubert Revolution, 89 Notre Dame l. Rev. 27, 30 (2013).
8 See Fed. R. Evid. 702, Advisory Committee Note to 2023 Amendments.
9 Fed. R. Evid. 702.
10 Kyocera Senco Indus. Tools Inc. v. Int'l Trade Comm'n, 22 F.4th 1369, 1376-77 (Fed. Cir. 2022).
11 Osseo Imaging, LLC v. Planmeca USA Inc., 116 F.4th 1335, 1340 (Fed. Cir. 2024).
12 Carnegie Mellon University v. Marvell Technology Group, Ltd., 807 F.3d 1283, 1302-03 (Fed. Cir. 2015) (rejecting challenge to damages expert's qualifications); Byrne v. Wood, Herron & Evans, LLP, 450 F. App'x 956, 965 (Fed. Cir. 2011), cert. granted, judgment vacated on other grounds, 568 U.S. 1190 (2013) ("Although it is true that possessing ordinary skill in the art does not automatically qualify a witness as an expert, there is no indication that any other qualifications are necessary.")
13 Osseo Imaging, 116 F.4th at 1340-41; Tehrani v. Hamilton Technologies LLC, No. 2022-1732, 2023 Wl 4231628, *3 n.3 (Fed. Cir. June 28, 2023).
14 Daubert, 509 U.S. at 592; Fed. R. Evid. 702(a).
15 Fed. R. Evid. 702, Advisory Committee Note to 1972 Proposed Rules (quoting ladd, Expert Testimony, 5 Vand.l.Rev. 414, 418 (1952)).
16 Id. (quoting 7 Wigmore § 1918).
17 Fed. R. Evid. 702, Advisory Committee Note to 2000 Amendments (noting that Rule 702 is "broad enough to require consideration of any or all of the specific Daubert factors").
18 Id.
19 Id.
20 Daubert, 509 U.S. at 593.
21 EcoFactor, Inc. v. Google LLC, 115 F.4th 1380 (Fed. Cir. 2024).
22 EcoFactor, Inc. v. Google LLC, 104 F.4th 243, 252 (Fed. Cir.), reh'g en banc granted, opinion vacated, 115 F.4th 1380 (Fed. Cir. 2024).
23 Id. at 261 (Prost, J., dissenting).
24 Id. at 257.
Originally published by IP Litigator, January/February 2025 edition
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