The Ghost in the Patent System: An Empirical Study of Patent Law’s Elusive 'Ordinary Artisan'

Abstract

Patent law shares with tort law the presence of a central character that structures judicial decision making. Much like the reasonable person in tort law, the “person having ordinary skill in the art” (or PHOSITA) in patent law is an anchor from whose vantage point the court must determine whether an invention is obvious, set out in sufficient detail, or infringed by a competitor. This vantage point 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. But court observers and legal scholars have also noted that the PHOSITA at times appears to do little work in driving doctrinal outcomes. Called at turns a “ghost,” a “mysterious” and an “enigmatic” character, the role of the PHOSITA in patent law is a bit like the curious incident of the dog in the night-time. Despite its theoretically expected central role in patent law, in some of patent law’s leading cases, it stands out for all of the work it does not do.

In this Article, we conduct the first comprehensive empirical study of the role of the PHOSITA across patent litigation. Through close readings of 700 trial and appellate court opinions as well as automated textual analysis of over 7000 cases we ask: how deeply do courts engage with factual evidence to define who the PHOSITA is? Does the identity of the PHOSITA, once established, in fact drive legal decision-making? How often does the Federal Circuit reverse District Court decisions based on incorrect factual or legal understandings of the PHOSITA? Do courts use different definitions of the PHOSITA for different doctrines?

What emerges from our empirical investigation is a deep disconnect between the centrality of the PHOSITA to patent law on paper and its empirical relevance to doctrinal outcomes. Despite its centrality to major patent law doctrines, and despite its ostensible claim to ground these doctrinal decisions in an objective reference point, the PHOSITA plays a surprisingly minor role in judicial decisions. This observation creates a paradox: as much as the PHOSITA is theorized as an outcome-determinative reference point, it does not appear, in practice, to drive judicial decisions. We suggest two central explanations for our findings. First, judicial decisions provide little guidance on how to reconcile definitions of the PHOSITA as an empirical, real-world construct with its hypothetical (and normative) dimension. Second, courts fail to tailor the PHOSITA to the underlying normative goals of each of the different doctrines that rely on the PHOSITA as a reference point, rendering the PHOSITA a normatively empty concept. We propose a solution that develops three normatively-distinct PHOSITAs for the patent doctrines of obviousness, enablement and infringement.