The use of expert testimony can be critical in supporting or defending a patent infringement lawsuit. Given the complex technical nature of many patent disputes, an expert witness is typically needed to explain the how the patented features and prior art would be understood by a person of ordinary skill in the art, the function and properties of accused techniques, and even the vocabulary used therein.
But the scope of an expert's testimony is not unlimited. The Federal Rules of Evidence set forth the requirements for any testimony that is proffered by an expert.1 These requirements are the enforced by the trial judge who is empowered with a "gatekeeping function" that "imposes a special obligation upon a trial judge to 'ensure that any and all scientific testimony . . . is not only relevant, but reliable.'" Carlson v. Bioremedi Therapeutic Systems, Inc., 822 F.3d 194, 199 (5th Cir. 2016) (citing Kumho Tore Co. v. Carmichael, 526 U.S. 137, 147 (1999)). The Supreme Court identified this gatekeeping function in Daubert v. Merrell Down Pharmaceuticals, Inc., 509 U.S. 579 (1993), noting that the Federal Rules of Evidence do not prevent the trial judge from "screening" proffered evidence for reliability based upon established scientific and legal principles.
This article addresses certain common grounds upon which parties to a patent infringement action may challenge the reliability of an opposing party's witness. While myriad potential grounds of objection exist, the article will focus on three:
- Failure to properly oversee testing of accused products;
- Improper bias or oversight introduced by the presenting party; and
- Reliance upon concurrent litigation as evidence of a lack of non-infringing alternatives.
Improper oversight of product testing
One goal of Daubert is to ensure the reliability of evidence presented by an expert. It follows logically that where an expert has not overseen or in any way supervised testing of accused (or other) products in a patent infringement case, the Court may properly exclude such evidence.
A purpose of introducing expert testimony during trial is to present technical or other specialized evidence for the jury, or finder of fact, to understand the underlying technology. Yet under Duabert, experts must present a basis for their opinions beyond shallow conclusions drawn from test results or other evidence over which the expert provided no oversight. Where the expert has not guided testing or examination of the products at issue, he or she may be unable to provide testimony related to the reliability of such tests. When details such as how the testing was performed, who performed it, the exact circumstances which were observed, and other important information are unknown to the expert, expert testimony based on such testing may lack the reliability necessary to justify inclusion in a case.
The Fifth Circuit's opinion in Hathaway v. Bazany is instructive on this point. 507 F.3d 312 (5th Cir. 2007). There, an expert offered little more than "personal assurances" that his conclusions were backed up by "police experience." Id. at 318. However, the Court disagreed, finding that the expert's reliance on a "host of unsupported conjectures . . . falls far short of a methodology." Id. An expert who cannot attest to the methodologies used and circumstances surrounding the testing which underpins their opinions cannot provide the reliability which is required by a court. See Viterbo v. Dow Chm. Co.¸826 F.2d 420, 424 (5th Cir. 1987) ("[W]ithout more than credentials and a subjective opinion, an expert's testimony that 'it is so' is not admissible.").
Similarly, in In re: Taxotere (Docetaxel) Products Liability Litigation, the Court noted that "Rule 702 and Daubert require an expert witness independently to valid or assess the basis for his or her assumptions." 26 F.4th 256, 268 (5th Cir. 2022). Where an expert did not oversee or direct testing, and has no way over verifying any of the methods used during that testing, the presenting party is unable to show the reliability of the proffered testimony. Thus, the party presenting the testimony cannot demonstration that "the expert's findings and conclusions are based on the scientific method, and, therefore, are reliable. This requires some objective, independent validation of the expert's methodology." Id. (quoting Moore v. Ashland Chem., Inc., 151 F.3d 269, 276 (5th Cir. 1998)). Where an expert themself cannot testify or otherwise inform the court of the source of their opinions with respect to testing and testing results, it follows that they cannot show the "underlying methodology" that is required.
Improper Bias by the Presenting Party
Part of the Court's gatekeeping function under Daubert is to ensure that improperly preferential or biased evidence is not present to the jury. To ensure this, the party seeking to present evidence must provide "some objective, independent validation of the expert's methodology." In re: Taxatere, 26 F.4th at 268. Such objective verification ensures that the party submitting the evidence is not merely using their expert as a mouthpiece for their own (potentially inadmissible) evidence. Parties to patent infringement actions may be technologically proficient and possess the internal ability to perform their own testing. While there is nothing implicitly wrong with a party performing, and in some cases presenting, the results of their own testing, such presentation is ripe for bias and must be carefully considered by a court before admission. Regardless, a party should not anticipate using an expert merely as a mouthpiece for that party's own testing results. See Wi-LAN Inc. v. Sharp Elecs. Corp., 992 F.3d 1366 (Fed. Cir. 2021); see also Dura Auto. Sys. of Indiana v. CTS Corp., 285 F.3d 609 (7th Cir. 2002) (holding that an expert is "not permitted to be the mouthpiece of a scientist in a different specialty"). Where an expert provides no input or guidance for a parties testing, but merely receives results from a party and is expected to reiterate those results to the court, any "margin of discretion . . . could be expected to be exploited to [the party's] benefit" since the testing was performed in order to further that parties own interests in the lawsuit. Dura Auto,. 285 F.3d at 615. This is especially true where the expert does not inquire into the identities and experience of those who have performed the testing or the circumstances of the testing.
The primary concern is reliability. Where an expert cannot (or does not) verify the source and integrity of the testing which they analyze, there is no reasonable expectation that any opinion formed therein can be considered reliable. Where the expert cannot influence or otherwise control the circumstances of testing, they again are unable to show reliability of the proffered testing. See Greger v. C.R. Bard, Inc., No. 4:19-CV-675, 2021 WL 3855474 (E.D. Tex., Aug. 30, 2021) (an expert cannot "simply repeat the opinions of others as his own when he has done nothing to verify the accuracy of the opinions"); Scrum Alliance, Inc. v. Scrum, Inc., No. 4:20-cv-227, 2021 WL 1725564 (E.D. Tex., Apr. 30, 2021) ("The task for courts is not to determine that '[an] expert's testimony is correct,' but rather that 'the testimony is reliable'") (quoting Moore v. Ashland Chem., Inc., 151 F.3d 269, 276 (5th Cir. 1998)) (emphasis in original).
Use of Co-Pending Litigation as Evidence of Lack of Non-Infringing Alternatives
Another area of potential concern arises where a party has engaged in litigation against other accused infringers, and attempts to use that litigation as evidence of a lack of non-infringing alternatives. Patent owners often assert patents against multiple parties (and in turn, against multiple accused products). As such, experts will often have access to these various different accused products across each of the cases, and will often be called upon to provide testimony related to various secondary indicia of non-obviousness, including a lack of non-infringing alternatives. But care must be exercised in attempting to do so.
First, where these other cases are ongoing, the conclusion that those alternatives (even assuming for the sake of argument that the accused products are viable alternatives) are infringing is at best premature and at worst, outright incorrect, depending on the outcome of the corresponding litigation. Second, testing in co-pending cases, and the subsequent results, are generally confined to the facts and admission in that particular case. An attempt to import the conclusions of that testing into a co-pending case can be improper, where the opposing party (and their own expert) cannot inquire into the circumstances of that testing, or examine the results. Rather, all that they have to examine are the bald conclusions presented by the opposing party's expert. See United Services Automobile Ass'n v. Wells Fargo Bank, N.A., No. 2:18-cv-00366, 2019 WL 6896648 (E.D. Tex., Filed Dec. 18, 2019) ("When evaluating Daubert challenges, courts must focus 'on [the experts'] principles and methodology, not on the conclusions that [the experts] generate.") (quoting Daubert v. Merrell Dow Pharma., 509 U.S. 579, 594 (1993)).
Conclusion
Even before evaluating the admissibility of evidence before a judge or jury during a trial, Daubert sets forth a gatekeeping standard for the reliability of proffered evidence. Given the technical nature of patent disputes and the necessary expertise of experts for these types of cases, patent infringement can provide ample opportunities to challenge the reliability of an expert's methodology. As seen above, one consideration is whether the expert has been able to oversee and direct the testing themself, or whether they relied upon information provided by a potentially biases party to draw their conclusion.
Footnote
1. Federal Rule of Evidence 702 specifically sets out these requirements:
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 content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
