Ordinary Skill in the Art: What Sets It Apart?

Key Takeaway:

Breaking down aspects of the skill level of the "person having ordinary skill in the art" in U.S. obviousness.

Table of Contents

Baseball is in the news these days, and the sport provides plentiful clever and helpful analogies—even with respect to the process of procuring patent protection for an invention. One can liken filing a patent application to its applicant stepping up to the plate and taking a swing for patentability. If the applicant’s claimed invention meets the patent law requirements, the applicant makes it around the bases to score an allowable patent claim. A clever cartoon depicted this in a comic written about another part of patentability—patentable subject matter under 35 U.S.C. § 101—which will be covered in another article. Stay tuned.

Image Credit: Julia Powles, Ilias Kyriazis (WIPO). Used with permission.

A claimed invention must be novel over the prior art—first base in the cartoon. Sometimes, patent practitioners will refer to this in another way, discussing whether the claimed invention is anticipated. The novelty inquiry generally concerns whether the claimed invention is, inter alia, “patented, described in a printed publication, or in public use, on sale, or otherwise available to the public.”135 U.S.C. § 102.This generally refers to whether a single reference from the prior art, for example, a widget that’s already on the market, “anticipates” the claimed invention. However, the patentability inquiry doesn’t stop with whether the claimed invention is novel or anticipated.

The claimed invention must also be non-obvious over the prior art. This article looks at this cartoon’s second base: non-obviousness.

What makes an invention non-obvious?

Beyond being novel, the claimed invention must also be non-obvious. In the United States, according to Section 103 of the Patent Act, non-obviousness centers on whether:

the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains.235 U.S.C. § 103.

Breaking this legal language down, there are a few things the Patent Office must take into account when determining whether an invention is obvious:

  1. The level of ordinary skill in the art;
  2. The scope and content of the prior art;
  3. Differences between the claimed invention and the prior art; and
  4. Secondary considerations (i.e., objective indicia of non-obviousness).3Graham v. John Deere, 383 U.S. 1, 17–18 (1966).

These factors compose what is often called the Graham inquiry, named after the landmark 1966 Supreme Court decision first compiling them. This article focuses primarily at the first factor—though it also touches the second—as it looks into the question, what defines the level of skill and knowledge an ordinary person would have to apply to combining or modifying the prior art?

The person described here not a real person and doesn’t have the biological or temporal limitations any of us would have. To realize “who” this person having ordinary skill in the art is, it’s critical to understand this person is imaginary.

An imaginary person with immense knowledge.

This imaginary person is often considered to be a precisely ordinary individual, having no more and no less skill than what can be considered “ordinary” in the field or endeavor. The so-called person having ordinary skill in the art, sometimes referred to by the acronyms POSITA, PHOSITA, or POSA, isn’t an expert. Nevertheless, the POSITA also is neither uneducated nor uninformed. As the Patent Office puts it:

The person of ordinary skill in the art is a hypothetical person who is presumed to have known the relevant art at the time of the invention. Factors that may be considered in determining the level of ordinary skill in the art may include: (1) “type of problems encountered in the art;” (2) “prior art solutions to those problems;” (3) “rapidity with which innovations are made;” (4) “sophistication of the technology; and” (5) “educational level of active workers in the field.”4Manual of Patent Examining Procedure (MPEP) § 2141(II)(C) (citing In re GPAC, 57 F.3d 1573, 1579 (Fed. Cir. 1995)).

Before anyone suggests a POSITA can be likened to an all-knowing automaton able to piece together whatever is needed to achieve a unique purpose, the Supreme Court disclaimed such a description, holding a POSITA is “a person of ordinary creativity, not an automaton.”5KSR International Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007).

A question in determining a POSITA’s knowledge is, what is prior art? A deeper answer will be the subject of another article. For this article’s purposes, prior art generally refers to patents, printed publications, public uses, public sales, or any other piece of information available to the public.6See 35 U.S.C. § 102(a). A common example for how far-reaching this definition can be comes from a Federal Circuit decision classifying as prior art a single copy of a doctoral thesis catalogued and shelved in a single library in Germany.7See In re Hall, 781 F.2d 897 (Fed. Cir. 1986). Prior art carries the adjective prior because it refers to art in existence by the time of filing (e.g., an invention made and sold after filing the patent application is generally not considered prior art). For the obviousness inquiry, it’s important this prior art be analogous art to—that is, sufficiently and appropriately related to—the field of the invention patent protection is sought for.

A POSITA has access to—and presumed knowledge of—every piece of analogous prior art in existence, simultaneously. Neither time nor biology bound a POSITA in this aspect. Sometimes, you’ll hear a POSITA described as being all-knowing, yet forever mediocre. In law school, my professor told us that it helps to think of a POSITA as sitting in a “prior art gallery” containing all analogous prior art.

Image Credit: Klaudia Piaskowska (Unsplash). Used with permission.

But what does it mean to be ordinary? This is a critical question, and is often fodder for rebutting obviousness rejections issued by the Patent Office. It’s a common place for arguing against an obviousness rejection—also known as a section 103 rejection, or a rejection under 35 U.S.C. § 103—as the examiner’s and applicant’s views on what it means to be of ordinary skill can differ significantly.

What does a POSITA know about oil wells?

Recently, the Court of Appeals for the Federal Circuit, referred to as the CAFC8The Court of Appeals for the Federal Circuit, in general, has jurisdiction over appeals regarding patent law from U.S. District Courts, as well as from proceedings at the Patent Office., in its nonprecedential decision in McCoy v. Heal Systems, LLC9Slip. Op. 2020-1484 (Fed. Cir. April 1, 2021)., took a tour of what it means to be the imaginary person having ordinary skill in the art.

McCoy addressed a patent, U.S. Patent No. 9,790,779 (the ‘779 patent) issued to James N. McCoy, for an apparatus for the production of well fluids. The device’s application is in the oil & gas industry, and in part assists in relieving pressure in the well.

Fig. 1 from U.S. Patent No. 9,790,779.

Heal Systems, Inc. petitioned for an inter partes review of the ‘779 patent, arguing that the claims of the ‘779 patent were anticipated (i.e., not novel) and obvious over the prior art. In making its case before the Patent Trial & Appeal Board (PTAB), Heal relied on expert testimony, arguing that a POSITA would have had access to the expert. The PTAB agreed with Heal, specifically stating:

that an ordinary skilled artisan at the time of the invention “would have had at least a Bachelor of Science degree in mechanical, petroleum, or chemical engineering, or a related degree, and at least 3–4 years of experience with downhole completion technologies related to deliquification or artificial lift and gas separation.”10Id. at 3 (quoting Heal Systems, LLC v. Echometer Company, IPR2018-01409, 42 (Pat. Tr. App. Bd. December 30, 2019)).

Further, the PTAB agreed with Heal’s assertion that a POSITA in this case “would have had access to and been able to consult with other experts in the oil well industry,” and such access would not render a POSITA “converted into [an] expert[].”11Heal Systems LLC, IPR2018-01409 at 43. This is a critical note, as the courts have long held the knowledge of a POSITA is not, and must be distinguished from, that of an expert. McCoy appealed the decision to the CAFC.

The CAFC confirmed this prohibition on the substitution of expert skill in the place of ordinary skill, by quoting its former case, Env’t Designs, Ltd. v. Union Oil Co., which emphasized,

the need to adhere to the statute, i.e., to hold that an invention would or would not have been obvious, as a whole, when it was made, to a person of ‘ordinary skill in the art’—not to the judge, or to a layman, or to those skilled in remote arts, or to geniuses in the art.12713 F.2d 693, 697 (Fed. Cir. 1983).

The CAFC indicated there may be circumstances where it is appropriate to consider a POSITA as having access to an expert. The court further addressed potential concerns regarding the breadth of the assertion that a POSITA could rely on an expert, explaining that such reliance would not necessarily be appropriate if such reliance is not routine in the art. The CAFC then ultimately concluded use of an industry expert who a POSITA could have appropriately relied upon did not constitute an improper substitution of the expert’s skill for a POSITA’s skill.

As explained in McCoy, the imaginary person would not only have access to analogous prior art, but a POSITA would also have access to assistance of industry experts in understanding the prior art, if such access and counsel can be considered ordinary in the field. However, this assistance is to be understood as not substituting for or supplanting the ordinary nature of the POSITA’s own skill in the art.


While the CAFC’s McCoy opinion is considered nonprecedential—that is, it does not “add[] significantly to the body of law”13Fed. Cir. Rule. 32.1(b).—it helps teach an important aspect of patentability. A person having ordinary skill in the art has access to a wider breadth of knowledge than any individual human reasonably could, and, where appropriate, may have access to expert counsel. Even so, a POSITA is not an expert and must not be conflated with one. For all the prior art a POSITA may have knowledge of, a POSITA’s skill with that prior art is nothing more than ordinary.

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