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District Court Excludes Expert’s Opinion on What He Believed a PTO Examiner Would Have Done Had the Plaintiff Disclosed Additional Information to the PTO as Speculative

In this patent infringement action, the Plaintiff moved to exclude the defendant’s expert, Mr. Carmichael, arguing that his testimony should be stricken because Mr. Carmichael “improperly opines on what he believes a PTO examiner would have done in a specific situation had he or she had additional information Carmichael had been provided.” In making its motion, the Plaintiff asserted that Mr. Carmichael’s report and testimony constitute “retroactive mind-reading of the thoughts of patent examiners.” Barry v. Medtronic, Inc., No. 1:14-cv-104, 2016 U.S. Dist. LEXIS 104118, *6-7 (E.D. Tex. July 19, 2016).

As an example, the Plaintiff pointed out that Mr. Carmichael intended to testify that the patent-in-suit would not have “issued as it did if the PTO had been aware of those prior installations and systems” and “if Mr. Squier had disclosed [information he allegedly withheld] the PTO would not have revived the patent and would have viewed the certification as unmistakably false.”

In response, Defendants contended that the Plaintiff mischaracterized Mr. Carmichael’s opinions, asserting that Mr. Carmichael’s report and testimony would assist the trier of fact in determining whether “from the perspective of a reasonable PTO examiner — the omitted information rises to the level of but-for materiality” and that Mr. “Carmichael’s opinion is not speculative but based upon his deep understanding of, and long experience with, PTO practice and procedure.”

In analyzing the issues, the district court noted that while courts have consistently recognized that experts may opine on the materiality of a patent applicant’s misrepresentations, omissions, and intent before the PTO, that does not entitle them to speculate about the outcome “if the examiner had different information.” The district court repeated that doing so is nothing more than “irrelevant speculation.” See Applied Materials, Inc. v. Advanced Semiconductor Materials Am., Inc., No. C 92-20643 RMW, 1995 U.S. Dist. LEXIS 22335, at *8 (N.D. Cal. Apr. 25, 1995).

The district court explained that “[i]n a similar circumstance, a district court in the Northern District excluded the testimony of a patent attorney-expert who was also ‘a former supervising patent examiner and former member of the Patent Office Board of Patent Appeals and Interferences” from providing his expert opinion “as to what the prior art teaches,’ ‘the `materiality’ of prior art,’ or what ‘the [PTO] examiner would have done if [the expert] had been the examiner, or if the examiner had different information.’ 1995 WL 261407, at *2 (N.D. Cal. Apr. 25, 1995). In doing so, the court noted that the defendant’s expert was not a technical expert, and lacked skill in the pertinent art. See id. at *2-3. The court found that testimony as to what the examiner ‘would have done’ under different circumstances was ‘irrelevant speculation’ that would impermissibly advise the jury on applicable principles of law. See id. at *3.”

The district court then determined that “[i]n essence, Carmichael is placing the proverbial cart before the horse by describing for the fact-finder how they should find in this circumstance rather than allowing them to make the determination based on the facts. In this case, despite Carmichael’s prior experience, his testimony oversteps his bounds of authority. Though Carmichael could theoretically opine on PTO policy and procedure, Defendants do not seek to present testimony on that issue. See, e.g., Sundance, 550 F.3d at 1361 n.2 & n.5 (allowing the defendant’s patent attorney-expert ‘testify as to patent office procedure generally’) (citing Bausch & Lomb, Inc. v. Alcon Laboratories, Inc., 79 F. Supp. 2d 252, 254-55 (W.D.N.Y. 2000)). Similarly, Carmichael’s testimony as to ‘reasonable practice’ by patent examiners would not help the jury to assess a fact in issue: instead, it would require him to give impermissible legal opinions. See Argus Chem. Corp. v. Fibre Glass-Evercoat Co., 759 F.2d 10, 13 (Fed. Cir. 1985) (The question of the appropriate standard for determining inequitable conduct in procuring a patent is one of law.)”

Accordingly, the district court granted the Plaintiff’s motion and excluded Mr. Carmichael’s report and testimony regarding the hypothetical behavior of the PTO.

Whitewater West Indus. v. Pacific Surf Designs, Inc., Case No. 3:17-cv-01118-BEN-BLM (S.D. Cal. Sept. 4, 2019)

The authors of are patent trial lawyers at Jeffer Mangels Butler & Mitchell LLP. For more information about this case, contact Stan Gibson at 310.201.3548 or

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