By James Juo.

In patent law, a patent is interpreted from the perspective of a hypothetical person of ordinary skill in the art, sometimes abbreviated as POSITA (and sometimes abbreviated as PHOSITA for a person having ordinary skill in the art). According to Professor Dennis Crouch, the abbreviation POSITA appears in 68% of PTAB cases having abbreviations as of 2018. Regardless of the abbreviation used, this legal construct is considered to have the normal skills and knowledge in a particular technical field or art.

“Factors that may be considered in determining level of ordinary skill in the art include: (1) the educational level of the inventor; (2) type of problems encountered in the art; (3) prior art solutions to those problems; (4) rapidity with which innovations are made; (5) sophistication of the technology; and (6) educational level of active workers in the field.” Environmental Designs, Ltd. v. Union Oil Company of California, 713 F.2d 693 (Fed. Cir. 1983).

A patent is interpreted and construed from the vantage point of a “person skilled in the art.” 35 U.S.C. 112(a); see also Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc) (“the ordinary and customary meaning of a claim term is the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention”).

Whether the invention recited in a patent claim would or would not have been obvious, as a whole, when it was made, is determined in view of a “person having ordinary skill in the art.” 35 U.S.C. 103; see also KSR v. Teleflex, 550 U.S. 398 (2007) (“A person of ordinary skill is also a person of ordinary creativity, not an automation.”).

An expert witness may testify in a patent case to provide “the particularized testimony of a person of ordinary skill in the art.” AquaTex Indus., Inc. v. Techniche Solutions, 479 F.3d 1320, 1329 (Fed. Cir. 2007) (“when the patent holder relies on the doctrine of equivalents, as opposed to literal infringement, the difficulties and complexities of the doctrine require that evidence be presented to the jury or other fact-finder through the particularized testimony of a person of ordinary skill in the art”). An expert witness also may possess more knowledge or skill than a person of ordinary skill in the art. Endress + Hauser, Inc. v. Hawk Measurement Systems Party, 122 F.3d 1040, 1042 (Fed. Cir. 1997) (improper to disqualify an expert for not being ordinary enough).

Recently, in Kyocera Senco Industial Tools Inc. v. ITC, No. 20-1046 (Fed. Cir. Jan. 21, 2022), the Federal Circuit further addressed the relationship between an expert testifying about the patented nailer technology, and the hypothetical person of ordinary skill in the art.

Kyocera brought the case before the International Trade Commission (“ITC”) against a competitor importing allegedly infringing gas spring nailers, and all of Kyocera's asserted patents were directed to “linear fastener driving tools” such as those that drive nails.

The POSITA in Kyocera was defined in that case to be a person having, among other qualifications, at least “two years' experience designing power nailers.”

Kyocera offered Dr. John Pratt as a technical expert to testify on claim construction, invalidity, literal infringement, and infringement under the doctrine of equivalents. “Dr. Pratt has advanced degrees in engineering and extensive experience in the design and manufacture of fastener driving tools”—but he lacked specific experience in power nailer design.

Because of Dr. Pratt's lack of experience in power nailer design, the administrative law judge (“ALJ”) for the ITC excluded his testimony on infringement under the doctrine of equivalents, but admitted his testimony as to literal infringement.

On appeal, the Federal Circuit held that Dr. Pratt should not have been allowed to testify on the patented technology.

            To offer expert testimony from the perspective of a skilled artisan in a patent case—like for claim construction, validity, or infringement—a witness must at least have ordinary skill in the art. Without that skill, the witness' opinions are neither relevant nor reliable. The opinions would not be based on any specialized knowledge, training, or experience that would be helpful to the factfinder. In fact, “[a]dmitting testimony from a person . . . with no skill in the pertinent art serves only to cause mischief and confuse the factfinder.” Sundance, 550 F.3d at 1362. That testimony would “amount[] to nothing more than advocacy from the witness stand.” Id. at 1364–65.

            This is true regardless of whether the witness is being offered to testify on literal infringement, doctrine-of-equivalents infringement, or both. Nothing about literal infringement makes an unqualified witness' testimony more relevant or more reliable. And the same goes for infringement under the doctrine of equivalents. The absence of relevant knowledge and the risk for abuse apply equally to both situations.

The Court noted that its prior AquaTex decision was not to the contrary because that case simply held that expert testimony is “always” required for doctrine-of-equivalents infringement and “sometimes” required for literal infringement. AquaTex was inapt to the Kyocera case because AquaTex did not address the minimum qualifications necessary for an expert to offer testimony from the perspective of a skilled artisan.

The Court also noted that its prior Endress + Hauser decision had recognized that, to testify as an expert, a witness must be qualified.

And to be qualified to offer expert testimony on issues from the vantage point of an ordinarily skilled artisan in a patent case, an expert must at a minimum possess ordinary skill in the art.

Because the level of ordinary skill in the art, adopted during claim construction and not appealed, was defined to require experience in power nailer design, and Dr. Pratt admittedly lacked such experience—the Court found that he “does not have ordinary skill in the art” notwithstanding his otherwise extensive experience in the design and manufacture of fastener driving tools. Thus, allowing him to testify “on any issue that is analyzed through the lens of an ordinarily skilled artisan” was error.

The patent attorneys at Thomas P. Howard, LLC are experienced in the prosecution of patent applications before the USPTO, as well as in enforcing patents or defending against infringement claims in litigation nationwide including in Colorado.