An International Guide to
Patent Case Management for Judges

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10.6.10 Evidence

Patent cases are characterized by motions – often many – directed at excluding or limiting the use of evidence, including motions attacking expert opinions.202 It is common practice to resolve such issues substantially in advance of trial so that the parties return with their presentations appropriately honed in accordance with the court’s limiting orders. Technical and economic expert witnesses

Daubert sets forth a nonexclusive checklist for trial courts to use in assessing the reliability of scientific expert testimony: (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.

Apart from the subject matter distinction between scientific or technical and economic (damages) experts, patent cases involve two distinct types of expert testimony. The first, common to most other types of litigation, involves applying an accepted technical, scientific, or economic methodology to facts established during the trial to reach conclusions about factual issues. An expert might testify, for example, about the results of their analysis to determine the chemical composition of the accused product. Because this type of testimony is directed to an analysis that the expert regularly performs outside of a litigation context, it falls squarely within the FRE 702 and Daubert frameworks. Consequently, it presents few novel issues.

The second type of testimony presents more challenges. In patent cases, an expert is often asked to use their scientific, technical, or specialized knowledge to evaluate a hypothetical legal construct. Examples include:

  • Who is a “person having ordinary skill in the art”?
  • Would a “person having ordinary skill in the art” believe at the time of alleged infringement that differences between the patent claim and the accused product are “insubstantial”?
  • At the time the patent application was originally filed, would a “person having ordinary skill in the art” have had a motivation to combine known ideas to create the claimed invention?
  • What royalty rate would the patentee and the infringer have agreed upon had they participated in a negotiation at the time of first infringement knowing that the patent was valid and infringed?

The court’s gatekeeping function is more nuanced in these areas. Because it reflects a hypothetical legal construct, it necessarily departs from the type of generally accepted, peer-reviewed methodology contemplated by FRE 702 and Daubert.

Courts have wide discretion to determine the process and timing for resolving the admissibility of expert testimony. Although they can address Daubert challenges in conjunction with summary judgment or motions in limine, these approaches tend to give short shrift to the Daubert inquiry. Thus, many judges consider the admissibility of expert testimony through a specific Daubert briefing or hearing schedule for Daubert motions in the case management order.

The optimal time for scheduling such motions is after experts are deposed on their reports, but well before the pre-trial conference. Timing the briefing and hearing this way will ensure that a full record is available, but also give the court adequate time to consider the merits of each challenge. In addition, early consideration of Daubert challenges prevents the risk of a party being denied any expert at trial, which in some circumstances can be a harsh sanction for a correctable error. For example, a common Daubert challenge to a damages expert is based on an alleged incorrect date for the hypothetical negotiation for the determination of a reasonable royalty. Determining this date can be challenging: not only because it depends on technical information related to infringement that is usually beyond the purview of damages experts, but also because the trial court’s summary judgment rulings can affect that date. In this circumstance, even if a damages expert’s methodology is adequate, the factual basis for the analysis may be incorrect as a matter of law. Once informed by the court’s summary judgment rulings, the expert can revise their analysis to include the correct information – so if the question is raised through an in limine motion on the eve of trial, it would be unjust to grant the motion and strike the expert. Consequently, many courts hear Daubert challenges at the same time as, but separate from, summary judgment motions. Patent law expert witnesses

Parties sometimes propose presenting expert testimony regarding patent law, procedures of the USPTO, patent terminology, prosecution history, or specific substantive (e.g., anticipation) and procedural (e.g., what a “reasonable patent examiner” would find material) issues through a patent attorney or former USPTO employee. In support of this testimony, parties often point out that the evidence rules specifically permit opinions on ultimate issues203 and the presentation of testimony without first specifying underlying facts or data.204

Testimony on issues of law by a patent law expert – as contrasted with a general description of how the patent process works – is usually inadmissible. Just as in any other field, it is exclusively for the court, not an expert, to instruct the jury regarding the underlying law. Conversely, testimony regarding the procedures and terminology used in patents and file histories, on the other hand, is often allowed. In many cases, however, this testimony might be redundant in light of a preliminary jury instruction explaining those procedures. Because a jury instruction is likely to be more neutral, it will usually be a preferable means of providing this information to the jury. A jury instruction, however, may lack sufficient specificity to explain a USPTO procedural event relevant in a particular case, and in that circumstance, expert testimony is more likely to be appropriate and helpful to the jury.

The admissibility of proffered patent expert testimony on ultimate issues will often depend on whether the expert is doing anything more than applying patent law to a presumed set of facts, essentially making the jury’s determination. This is particularly true if the proffered patent expert has no relevant technical expertise. Thus, a patent expert’s opinion regarding matters such as infringement, obviousness, and anticipation based on technical conclusions that are assumed or provided by a different expert is usually improper. Similarly, testimony applying patent law to issues intertwined with patent procedure, but dependent on technical conclusions supplied by others, such as the appropriate priority date of a claim in a continuation application, is usually inappropriate. Conversely, if the patent expert also has relevant technical expertise, she should be equally able to provide expert testimony within that expertise as would be any nonlegal expert with similar technical expertise.

In trials to the court, when there is no concern regarding jurors’ overreliance on expert testimony, courts more freely admit the testimony of patent law experts. This includes, for example, testimony regarding whether a reasonable patent examiner would deem particular prior art or statements important in an inequitable conduct determination. Courts have found such testimony helpful and allowed it.205

Testimony is sometimes offered regarding the abilities of patent examiners, their workloads, time spent on applications, or similar matters. This testimony, which is meant to bolster or undermine the statutory presumption of validity, is improper.206 The deference the jury should give to the actions of the patent examiners is an issue of law like any other. Inventor and technical employee witnesses

Inventors and other technical employee witnesses often testify at trial regarding the invention and other technical matters. These witnesses frequently would qualify as experts and, if properly disclosed as testifying experts, appropriately may provide expert testimony. Because their duties likely do not “regularly involve giving expert testimony,” no expert report is required by such employees absent special order; however, ordering such a report usually is appropriate and is a provision that might be included in the case management conference order.207

If inventors and other technical employees are not disclosed as experts, difficult line-drawing questions can arise regarding their testimony. For example, when an inventor or co-employee testifies regarding the invention to a jury, it is usually necessary to accompany the testimony regarding historical acts with an explanation of the technology involved. These explanations are sometimes challenged as undisclosed expert testimony. Other testimony that often draws a challenge is inventor or employee testimony regarding the nature of the prior art at the time the invention was made. While testimony about the invention and prior art may be highly technical, it may involve the description of historical facts without the expression of opinion. In that event, the non-opinion testimony is proper without expert disclosure. Such testimony, however, is sometimes employed in an attempt to introduce undisclosed opinion into evidence. Courts have discretion to admit into evidence demonstratives that summarize admissible evidence.208 Motions in limine

Motions in limine provide the court with an opportunity to establish procedures and substantive limitations that will streamline the evidence, shorten the trial, and reduce jury confusion. Although substantive to some degree, these motions largely implicate procedural requirements and the evidentiary basis for expert testimony. For this reason, some courts choose to hear motions in limine at the outset of a trial so that they are better acquainted with the disputes that are likely to arise, and then continue some portion of them until the issues are fleshed out during the course of the proceeding. Deferring these issues to trial can extend and interrupt the proceedings.

Motions in limine can cover a broad range of issues of concerns. Examples include:

  • a motion to bar a comparison between the accused product and an embodying product sold by the patentee (out of concern that the jury will focus on the patentee’s product as opposed to the claimed invention);
  • a motion to preclude undisclosed prior art (35 U.S.C. § 282(c) requires such disclosure at least 30 days before trial);
  • a motion to preclude a claim or defense based on a failure of proof;
  • a motion to preclude an expert from testifying about issues that were not identified in the expert’s report;
  • a motion to bar reference to related proceedings in the Patent Office; and
  • a motion to preclude the use of “patent troll” or other pejorative terms in referring to nonpracticing entities.

The resolution of these motions can involve legal questions as well as the facts and litigation process of the particular case.

The range of potential in limine motions can inundate judges as they are preparing for trial. In addition, some in limine motions might be disguised summary judgment or Daubert motions. Consequently, several judges implement rules to consolidate, streamline, and prioritize such motions, including requiring that:

  • all motions in limine and responses shall be filed together in the proposed pre-trial order;
  • each side shall be limited to three in limine requests, unless otherwise permitted by the court;
  • the in limine request and any response shall contain the authorities relied upon; and
  • each in limine request may be supported by a maximum of three pages of argument and may be opposed by a maximum of three pages of argument, and that the side making the in limine request may add a maximum of one additional page in reply in support of its request.
  • Additionally, if more than one party is supporting or opposing an in limine request, such support or opposition shall be combined in a single three-page submission (and, if the moving party, a single one-page reply), unless otherwise ordered by the court.