Lawyers have the odd habit of speaking in our own, often pointless, patois. Why do we say inter alia? Ceteris paribus? De benne esse? Is it all to save the occasional word through the vagaries of Latin grammar? Is it a plot to make our work less comprehensible to the layman, and thus to puff ourselves up? Are we just word nerds?
The issue is often worsened when legalese butts up again other technical jargon, as in a patent specification. Hence the constant claim construction battles over the "plain and ordinary meaning" of a crumfustulator among wild-animal podiatrists.
(Eds. note—should have saved the picture for the crumfustulator. You'll just have to use your imaginations for that one)
But what happens when the patent does use words with a plain meanings to both the expert and the novice? Would that intriguing state of affairs be a boon or a curse in a patent case?
Last week's opinion in Lab. Corp. of Am. Holdings v. Natera, Inc., C.A. No. 21-669-GBW (D. Del. June 5, 2025) (Mem. Order) shed some light on the question. The plaintiff there had a source code expert who opined on how the code operated, but explicitly did not provide any opinion on whether the relevant product infringed (that was done by a different expert who relied on the source code expert's report). Indeed, he testified that when he wrote the report he hadn't even read the Court's claim construction opinion. Nevertheless, his report used several common phrases contained in both the patents and the Court's Markman Order including "sequence reads" and "combining."
Defendant thus moved to preclude this testimony under Daubert, arguing that by using the claim language, the expert was really offering a stealth infringement opinion which was likely to confuse the jury. Judge Williams denied the motion, but recognized the force of the argument for preclusion:
In this instance, the Court finds plausible Defendant's assertion that "permitting Dr. Earl's supposedly coincidental use of the claim terms ... is highly prejudicial." . For example, despite Dr. Earl's testimony that he is not proffering infringement testimony, jurors might assume that the testimony found in Paragraph 15 of Dr. Earl's Opening Report opines on whether accused systems/methods practice the "sequence reads" limitations. Defendant's assertion, however, is a "cursory argument[]" that it fails to "fully develop[]." Thus, at this time, the Court denies Defendant's request to exclude Dr. Earl's testimony.
Id. at 11 (internal citations omitted).
There remains a bit of hope for defendant however, as the Court ordered the parties to meet and confer on "stipulation whereby, to ameliorate the possibility of juror confusion, Dr. Earl would provide the same substantive testimony without invoking the challenged words that the Court has construed," and further ordered letter briefing on any issues that remained if the parties were unable to reach agreement.
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