Beyond the Specification: Why PHOSITA Should Be Defined by the Claims
Patent law’s “person having ordinary skill in the art” — the PHOSITA — has always been more than a doctrinal construct. It’s the invisible character whose competence defines the line between invention and obviousness. But who exactly is this person, and where do we find them: in the specification’s story or in the claims’ boundaries?
In Axonics v. Medtronic, the PTAB took the specification-first approach, defining the PHOSITA as a specialist in sacral neuromodulation even though the challenged claims never mentioned that field. The result? Broader claims tested against a narrower “ordinary” skill level — a mismatch that makes patents harder to invalidate and potentially overprotective.
Defining the PHOSITA through the claims instead would realign the doctrine with its purpose. Obviousness tests the boundaries of a patent monopoly; it should therefore be judged from the perspective of someone working at those boundaries, not confined to the narrower world the inventor chose to describe. The Manual of Patent Examining Procedure itself directs examiners to evaluate “the claimed invention,” not the disclosed one.
The question may seem technical, but it goes to the heart of innovation policy. A PHOSITA defined too narrowly risks granting monopolies over what specialists in broader, more advanced fields would find obvious. In an era of cross-disciplinary technology — from AI-driven medical devices to synthetic biology — it’s a reminder that the legal definition of “ordinary skill” must evolve with how innovation actually happens.
Excerpt adapted from my article “Should a PHOSITA Be Defined by the Specification or by the Claims?,” originally published in AIPLA Innovate Magazine (June 2022).
