pp. 247-302 (online version)
Published in November 2022
Introduction: Patents are widely understood to serve two interrelated, yet conceptually distinct, functions: They are at once legal and technical documents. Like a property deed, patents set out the metes and bounds of an inventor’s property rights. But patents also serve an important technological function by disclosing and explaining the technical details necessary to practice an invention, therefore contributing to the storehouse of technological knowledge that drives innovation. The “person having ordinary skill in the art” (or “PHOSITA”) emerged as a fulcrum to support this dual role. The word “ordinary,” however, is deceptive. Although it evokes common-sense behavioral qualities that any “average” practitioner would have, it also compiles ideal characteristics not reflected by any real-world actors, therefore making understanding who the PHOSITA is and how the PHOSITA would act as much of a theoretical as a factual exercise.
Neither a real-world “person” nor a complete legal fiction, the hypothetical ordinary artisan is meant to help judges and juries achieve both technological and policy goals. From a technological perspective, the PHOSITA’s vantage point ensures a patent contributes to the storehouse of knowledge and makes a technologically meaningful advance. From a policy perspective, the PHOSITA ensures that patent rights advance social welfare. This dual role can perhaps be seen most clearly in the obviousness inquiry, meant to differentiate trivial technological advances from those meriting patent protection. The obviousness PHOSITA is somewhat of a plodder with only a minimum of creativity but a wealth of factual knowledge—not likely representative of any average or ordinary inventor in any particular field. From a normative perspective, however, limiting a PHOSITA’s creativity arguably helps identify those inventions that would take place in a counterfactual world where only market, but not patent, incentives are present.
Although emerging initially as a common law innovation in the obviousness doctrine, the concept of the PHOSITA quickly expanded to serve as a reference point in disclosure doctrines (concerned with ensuring the inventor adequately communicates details of the invention to the public) and infringement doctrines (concerned with setting out the metes and bounds of the invention). The modern-day PHOSITA scaffolds every major patent law doctrine, providing a unifying prism to determine patent validity and infringement, both at the patent office and in the courts. The PHOSITA’s 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.
And yet, 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, it often appears to do little real, outcome-determinative work in the very patent doctrines it is supposed to help define.
In this Article, we present a large-scale empirical analysis of the PHOSITA in litigation. Through close readings of seven hundred court opinions as well as automated textual analysis of over seven thousand 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? Is the court’s depth of engagement correlated with the expected technical difficulty of the particular invention at issue? And, have recent Supreme Court decisions that emphasize the centrality of the PHOSITA had an impact on lower courts’ decisions?
We show that, although the PHOSITA is implicated in a wide variety of patent doctrines, its appearance in litigation is in large part related to three key doctrinal areas: obviousness, enablement, and claim construction. We find little evidence to suggest that the PHOSITA plays an outcome-determinative role in litigation. On the contrary, we find that when courts do engage with skilled artisan related issues, they tend to do so in quite perfunctory ways. The majority of cases that make PHOSITA-related holdings provide little-to-no reasoning or evidentiary support to justify those holdings. It is only in relatively rare instances that the court even provides limited reasoning or evidence to support its PHOSITA holdings, and quite rare indeed to see thorough reasoning and evidentiary support for holdings related to the PHOSITA. Although one might expect courts to engage in more reasoning or demand more evidentiary support in technologically complex cases, our analysis finds no evidence that this occurs. Finally, despite predictions that a trio of Supreme Court decisions—KSR International Co. v. Teleflex Inc., Nautilus, Inc. v. Biosig Instruments, Inc., and Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc. —would dramatically increase the importance of the PHOSITA’s perspective in litigation, we see only a modest increase in courts’ depth of engagement following KSR and no change following both the Teva and Nautilus decisions.
In brief, 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. 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. Indeed, our empirical research shows the PHOSITA to be a monolithic construct that remains unchanged across doctrines, rather than a nimble concept that is responsive to the different underlying normative goals of the doctrines it mediates. Put differently, courts do not sufficiently examine whether the PHOSITA should be a designer and researcher, a user or reader of the technology, or a competitor in the same technological field. Because deciding whether, for example, the PHOSITA is a patent reader versus a researcher requires also engaging with the normative goals underlying each doctrinal area, addressing these questions would not only provide normative content to the PHOSITA’s real-world characteristics, but would also help achieve its dual technological and policy goals. These explanations also ground our reform proposals for reimagining the PHOSITA’s role as a mediator between patent law’s technical and normative goals across patent doctrines.
The Article proceeds as follows: Part I provides a brief historical background of the concept of the PHOSITA, situating its origins as a common law innovation in the obviousness doctrine and tracing its expansion to other validity and infringement doctrines. Part II lays out our empirical findings. Part III turns from the empirical to the normative, developing a framework to reconcile the PHOSITA’s empirical and normative dimensions. We build upon literature in tort law about the reasonable person and in sociology about expert communities, to develop three different PHOSITAs (the obviousness, enablement, and infringement PHOSITA) that reflect the distinct normative goals of each doctrine.
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