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Level of Ordinary Skill in the Art
Practical Law Glossary Item w-020-2656 (Approx. 4 pages)
Glossary
Level of Ordinary Skill in the Art
In patent law, a factual finding used as a reference in evaluating the patentability of an invention (during patent prosecution) or the infringement or validity of a patent claim (during patent enforcement litigation or challenges at the Patent Trial and Appeal Board). The level of ordinary skill must be determined as of the effective filing date of the patent application.
The relevant art is the general subject matter of the claimed invention. In determining the appropriate level of ordinary skill, a fact finder may consider:
- The inventor's educational background and experience.
- Types of problems encountered in the art.
- Prior art solutions to those problems.
- Rapidity with which innovations are made in the art.
- Sophistication of the technology.
- Educational background and experience of those working in the art.
The level of ordinary skill inquiry is used as a reference when:
- Construing patent claims. For more information on claim construction, see Patent Litigation Claim Construction Toolkit.
- Comparing a patent claim element to an accused product in an infringement analysis under the doctrine of equivalents. For more information on equivalence, see Practice Note, Patent Infringement Claims and Defenses: Doctrine of Equivalents.
- Determining what a prior art reference or event discloses or teaches, including whether the reference inherently discloses a claim element. For more information on inherency, see Practice Note, Patent Litigation: Anticipation Defense: Inherent Disclosure.
- Determining whether a pending or issued patent claim would have been obvious in view of the prior art. For more information on obviousness, see Practice Note, Patent Litigation: Obviousness Defense.
- Evaluating whether a pending or issued patent claim meets the written description, enablement, and definiteness requirements. For more information about these specification requirements, see Practice Note, Patent Litigation: Specification Requirements.
Patent counsel often refer to a person at the level of ordinary skill in the art as a person:
- Having ordinary skill in the art (abbreviated PHOSITA).
- Of ordinary skill in the art (abbreviated POSITA).
- Skilled in the art.
Determining the level of ordinary skill in the art of the claimed invention is also important when retaining an expert witness, who should qualify as a person of at least ordinary skill in the art of the asserted patents. For more on expert witnesses, see Patent Litigation Expert Toolkit.