Whether to Use an Expert

Assuming that the court will consider hearing testimony as part of the process of claim construction, the question then becomes whether or not to use an expert. Most often, experts are used to explain technically complex subject matter and provide background information to aid the court. Commonly, the claims will use technical terms that are not explicitly defined in the specification but are otherwise understood by those skilled in the art. Without an understanding of the technology, the court would not even be able to interpret the words. An expert can show how those technical terms are properly interpreted in the relevant field. The same explanation from an attorney or even a technical dictionary or handbook may not carry the same weight.

While each side in a suit for patent infringement usually argues that the "plain meaning" of the claim language and the intrinsic evidence support its position, the patent claims and specification usually favor one position more. For example, there may be an ambiguity in the claim language that is not apparent from its "plain meaning." One side will argue "plain meaning" while the other will seek to have the court "interpret" the claim language. Since even ordinary words can be subject to different meanings in different contexts, an expert may be able to show that what seems apparent on its face is not really so clear.

There may other reasons to use experts as well. An obvious one is that the other side is going to use an expert. If the court does not exclude all expert testimony, the opponent's expert must be at least met with an equally qualified expert. Similarly, a truly outstanding expert may justify an attempt to have him or her testify at the Markman stage. The Markman hearing may be used as an opportunity to establish the expert's credentials and credibility in the eyes of the court before trial. Likewise, an expert witness, while not an advocate, may be used to sell the case to the court, for example, by establishing the technical merits and advantages of the invention. On the other side, the expert may be able to explain the background of the invention in such a way as to demonstrate that everything disclosed and claimed in the patent was already known, setting the stage for a future validity attack.

There are also some definite risks in using expert witnesses for claim construction. Most significantly, conflicting expert testimony may confuse the court or make the case unnecessarily complicated when it can be decided on much simpler grounds. Using expert witnesses necessarily makes the proceedings more complicated (and more expensive) when the court may not give the testimony any meaningful weight. Finally, the use of expert witnesses, no matter how good, entails some risk because they are human and under pressure. Placing the case in the hands of an expert means some loss of control and the risk that something will go wrong.

Indeed, if all the expert can do is read the intrinsic evidence and offer his or her opinion on claim construction, then the risk may not be worth it. If the intrinsic evidence is strong, and the "plain meaning" already favors the preferred claim construction, then the better strategy would likely be to try to prevent any experts from testifying.

In the end, the decision whether or not to use an expert witness in the process of claim construction is a difficult strategic call. The decision depends on many factors, from the strength of the expert to the strength of the case based on the intrinsic evidence. Even if the case would benefit from expert testimony, however, the most difficult hurdle may be convincing the court to hear it.

Convincing the Court

As discussed above, the Federal Circuit has not mandated any particular procedure that must be followed in claim-construction proceedings. The Federal Circuit has indicated that trial courts may consider extrinsic evidence, including expert testimony, for education and background, even where the intrinsic evidence is sufficient to construe the claims. If the trial court is not inclined to hear testimony at the Markman stage, however, then stressing its educational value will likely not be enough.

Rather, the most likely way to convince the court that it needs to hear expert testimony is to show the existence of technical terms in the claims that are not defined in the patent specification. Faced with a choice between competing definitions of technical terms, where the answers are not readily supplied by the intrinsic evidence, the court may be willing to turn to outside help. Of course, this may also require convincing the court that seemingly ordinary claim terms in fact have a technical meaning in the particular field.

Moreover, to convince the court to hear expert testimony, one must provide an expert who has the right technical expertise to assist the court.

How to Select and Use an Expert Effectively

Fed. R. Evid. 702 provides for testimony by experts: "If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise." Thus, as a threshold matter, any expert must have "scientific, technical, or other specialized knowledge" that will assist the court. In this respect, it is most important that the expert have the right technical background for the subject matter at issue. Although many experts may be able to explain the technology adequately, if the expert is going to testify about particular meanings of a technical term, he or she must be qualified in the relevant technical field.

In selecting an expert for issues of claim construction, academic credentials are not always paramount. Under Rule 702, expertise may come from "knowledge, skill, experience, training, or education," so advanced degrees are not mandatory. While academic credentials may impress a jury, a court is more likely to believe an expert who can explain things simply and can back up his or her opinions.

Occasionally, a plaintiff-patentee uses the inventor of the patent-in-suit as a claim-construction witness. After all, the inventor obviously has experience in the relevant field. And who better to explain what is meant in the patent?

In reality, inventor testimony is so strongly disfavored by the courts that it is almost not worth putting on at a Markman hearing. Among the types of extrinsic evidence available, inventor testimony is the least persuasive. It is seen as inherently biased and not deserving of much weight. An independent technical expert, if affordable, is always better than the inventor. If the Markman hearing is going to be an extended proceeding with multiple witnesses-which is a rare occurrence these days-the inventor may provide useful background information if there will also be an independent technical expert.

Whoever is selected to testify, an expert witness should be used to make the case more understandable by making it simpler. Often times, expert "tutorials" on the technology provide so much information that only a portion can be readily absorbed and comprehended. With experts, less is more. The temptation for most experts will be to provide more information, believing that if they explain more, then comprehension will increase. Rather, an expert's testimony should be focused only on the critical areas necessary to decide the case, not on a complete review of the history of the technology.

To bolster credibility, the expert should rely on more than opinion. Other sources, particularly written materials, should back up the opinion. Textbooks, handbooks, and technical dictionaries can be used to lend weight and credibility to the expert's views.

In this respect, make sure that any testimony offered by the expert will stand up to a challenge under Daubert v. Merrill Dow Pharmaceuticals, Inc.,35 Daubert challenges, in brief, are challenges to the admissibility of expert testimony based on Fed. R. Evid. 702. Daubert applies to "technical or other specialized knowledge" under Rule 702 as well as "scientific" knowledge.36 Under Daubert, proposed expert testimony is subjected to analysis of four factors: (1) Was it subjected to peer-review publication? (2) Does it have a known or knowable error rate? (3) Is it generally accepted in the relevant scientific field? and (4) Has it been tested or is it testable? Although these factors do not all necessarily apply to the type of expert testimony that will be offered for claim construction, external indicators of reliability, such as those provided by textbooks and handbooks, may be needed to meet a challenge under Daubert. Moreover, expert testimony that is at odds with the intrinsic evidence will be automatically rejected as well.

Thus, it is critical that the expert testify consistently with the intrinsic evidence. This does not mean that the expert should simply read the patent and its prosecution history and give the court an opinion on how the claims should be interpreted. Indeed, such testimony could be seen as usurping the court's role. As with any expert, prior writings and testimony should be carefully reviewed to make sure that there are no surprises.

In actually presenting the testimony, the expert should take full advantage of available presentation technology. Some of the most helpful information may come from seeing a live demonstration or a video tape of the patented invention in use or operation. Computer animation and graphics can be used to explain complex scientific principles. Again, care should be taken to avoid overloading the court with information. The goal is to simplify the issues in a way that makes the position taken seem logical and inevitable.

Occasionally, the court will not want to hear testimony from the parties' experts. Rather than witnessing a "battle of the experts," where the parties advance their positions through their hired experts, the court will turn to a neutral technical expert.

Using Court-Appointed Experts

Some courts have taken the consideration of extrinsic evidence in connection with claim construction even further by appointing technical advisors under Fed. R. Evid 706. The courts appointing these experts have cited the desire to obtain background and education into the technology from an independent source.37

One court extolled the virtues of using a court-appointed expert in connection with claim construction, stating that the court "learned more technical data in a 45-minute discussion with [the court-appointed expert] than I would have learned in two days of formal testimony" and that the "efficacy of the process can not be overstated."38 The court explained that it was not denigrating cross examination, but said that "fair cross presumes an understanding of the data examined. In recondite fields of scientific endeavor, however, my understanding is deficient and I need help-much like the help one gets from a law clerk in a recondite field of law."39 The court was careful to note, however, that it drew its own independent conclusions.

In contrast, at the May 2001 Federal Circuit Bench and Bar Conference, with a single exception, a panel of district court judges questioned the value of court-appointed technical experts under Rule 706, stating that they were often not helpful, particularly where a dialog could not be had between the judge and the expert. One judge opined that counsel must do a good job teaching their own experts how to teach the judge because the judge found the explanations of the parties' experts much more understandable than those of the court-appointed expert.

Conclusion

The procedures followed by district courts in construing patent claims will continue to evolve. Although the trend in many courts is away from conducting Markman hearings with live testimony, expert witnesses can and should continue to play a role in claim construction for some cases. Both lawyers and judges should consider using an expert to explain complex technology or when the claims contain technical terms. But experts must still be used cautiously, and with regard to their proper role, so that the court not only arrives at the correct claim construction but also does so in the right way.