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Patent Docs: The question of expert testimony in patent cases
When is an expert not an expert? In patent litigation the answer is (usually) simple: when she hasn’t been qualified as an expert according to the rules of civil litigation. And a defendant in a recent infringement lawsuit found that out the hard way, when its success in invalidating claims to the asserted patents was overturned on appeal at the Federal Circuit.
The case, HVLPO2 v. Oxygen Frog LLC, involved devices and methods for controlling oxygen-containing airflow used by torch glass artists. The question posed to the jury was whether the claimed apparatus and methods were obvious over two prior art references. The defendant proffered testimony of a layman (who also happened to be the creator of one of the prior art references, an Internet video presentation) who stated that the invention would have been obvious to him. The judge overruled plaintiff’s objection to this testimony, that it was an opinion by a layman, but explained to the jury the witness’s status as a layman (a stratagem that ultimately was deemed insufficient by the Federal Circuit).
The basis for the Federal Circuit to reverse the jury determination on appeal (technically, the court reversed denial by the district court of plaintiff’s motion for a new trial) was that the law provides protections to patentees from having a layman provide opinion testimony when she is not legally qualified as an expert. One of these protections comes from the rules of evidence, which limits opinion testimony to someone who has “knowledge, skill, experience, training or education” and whose testimony would “help the trier of fact to understand the evidence or determine a fact in issue.” Moreover, the rule requires that any such testimony be based on “sufficient facts or data” and is “the product of reliable principles and methods,” which the expert has applied to the facts of the case. These requirements are much more rigorous than merely having a witness state her opinion, and provide the opponent a structured opportunity to challenge the opinion not found under the circumstances in this case.
Procedurally, court rules provide that any such expert witness be identified before trial and that a proponent of the expert provide their adversary with the facts and bases of any opinion, typically in a written expert report that can be challenged at deposition and by an opposing expert report from the other side. These procedural protections act to ensure that opinion-reliant issues are fully fleshed out before trial (which can increase the likelihood that a case will settle). Under the circumstances in this case none of those protections were available to patentee, creating another reason that the Federal Circuit found error (termed an abuse of discretion) by the district court.
The question of whether a layperson can testify as to his opinions becomes important when, as here, those opinions are directed to important factual or (more typically) legal issues in the case. Here the question was obviousness which, while a legal question depends in large part on an understanding of the facts. Those facts include what the prior art teaches and how those teaching would be understood by a hypothetical person having ordinary skill in the art. Even the question of who such a person would be can be contentious: for example, in pharmaceutical cases such a person is usually one with an advanced degree in the relevant scientific discipline, and/or several years of experience at the bench or in a drug development or production capacity. And experts in patent cases tend to have their focus directly on the relevant facts upon which they base their opinions; in contrast here the testimony was merely “in your opinion would the claimed invention have been obvious” and the answer “yes.”
The last basis for the Federal Circuit’s decision to reverse invalidation of the claims in suit based on obviousness was that it was unclear the extent to which the layman’s improper testimony influenced the jury. Absent the procedural and evidentiary protections plaintiff patentees typically rely upon regarding expert testimony, neither the parties, the district court, nor the Federal Circuit had any way to evaluate how important this testimony was for the jury in making its decision to invalidate the claims as being obvious. Even the instruction to the jury, regarding the limitations it should place on its consideration of this layman’s testimony, was insufficient according to the appellate court to ensure the jury did not give improper weight to the testimony, because once given to the jury there is little opportunity to discern for individual jurors or the jury as a whole what evidence was more or less persuasive. This creates the possibility that the decision was improperly made and thus entitled the patentee to a new trial.
The complexities of most pharmaceutical litigation provide a generally greater level of safeguard against having a jury consider expert testimony from a layperson (and many but not all such trials are heard by a judge alone and are not presented to a jury). However, the line between casual opinions and expert ones can be hard to draw in some cases; the best practice is to limit any opinion testimony to exclude outcome-determinative issues, which is most cases will prevent questions eliciting opinions from being proffered to anyone not legally qualified to give expert testimony.