The Ghost in the Patent System: An Empirical Study of Patent Law's Elusive “Skilled Artisan”

Laura Pedraza-Fariña, Ryan Whalen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Patent law shares with tort law the presence of an artificial character that structures judicial decision-making. Much like the reasonable person in tort law, the “person having ordinary skill in the art” (or PHOSITA) frames judicial inquiries into such central patent law questions as whether an invention is obvious, set out in sufficient detail, or infringed by a competitor. The PHOSITA's perspective is considered so self-evident and foundational to the field that virtually every patent textbook and judicial opinion emphasizes that doctrinal outcomes are tied to the technical perspective of the PHOSITA, not that of the judge or an ordinary observer. Despite the field's acknowledged reliance on this artificial character, and the Supreme Court's reaffirmation of its importance, scholars and jurists have raised doubts as to whether the PHOSITA in fact plays an outcome-determinative role in the resolution of patent disputes. In this Article, we conduct the first comprehensive empirical study of the role of the PHOSITA in patent litigation. Through close readings of seven hundred trial and appellate court opinions as well as automated textual analysis of over seven thousand cases, we evaluate the way lower courts create their artificial PHOSITA, the construct's impact on legal decision-making, and the influence of Supreme Court interventions on lower court outcomes. We find that the PHOSITA plays a surprisingly small role in judicial decision-making, even in the aftermath of Supreme Court decisions that emphasize its centrality. Unpacking these results, we show that lower courts lack guidance in how to reconcile competing conceptions of the PHOSITA as a real-world construct tied to specific facts and as a legal construct designed to advance normative goals. We argue for a normative use of the construct and offer a structure for lower court decision-making. By crafting different versions of the PHOSITA tailored to the normative goals of obviousness, claim construction, and infringement that patent law seeks to answer, lower courts can create a PHOSITA that, however artificial, works more effectively to advance the goals of the patent system.

Original languageEnglish (US)
Pages (from-to)247-302
Number of pages56
JournalIowa Law Review
Issue number1
StatePublished - Nov 2022

ASJC Scopus subject areas

  • Law


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