Is Novelty Obsolete? Chronicling the Irrelevance of the Invention Date in U.S. Patent Law

56 Pages Posted: 24 Mar 2010

Date Written: March 22, 2010


The US first-to-invent patent regime is unique in that it allows a patent applicant to assert priority rights back to the invention date. The level of reliance on inventorship rights is important because it informs the longstanding policy debate over whether the US should conform to a first-to-file system as well as for patent applicant strategy. Prior studies have considered the use of inter partes interference proceedings. However, that approach necessarily ignores ex parte prosecution.

This paper presents a normative study of patent applicant use of invention-date rights during ex parte prosecution. Three sources inform the primary results: the prosecution history files of 21,000 patent applications filed in the past decade; a survey of 1,000 patent practitioners regarding their use of the novelty provisions of the Patent Act; and a collection of 11,000,000 prior art references cited in recently-issued patents. Additional compilations of prosecution file histories for patents identified as either (1) valuable or (2) worthless supplement these data sets and allow for an evaluation of the differential importance of the novelty rights. Finally, a set of opinions from the Board of Patent Appeals and Interferences (BPAI) evidences the difficulty of proving a prior invention date.

During prosecution, most patent applicants are faced with non-102(b) prior art that could be antedated. Yet, very few applicants actually attempt to assert prior-invention rights. A miniscule 0.1% of cases in my large sample included an assertion of novelty rights that directly led to an issued patent. The process of claiming priority to a pre-filing invention-date requires that an applicant prove prior conception and due diligence or reduction-to-practice. The difficulty of attempting to prove these elements are laid-out in a set of administrative patent appeal decisions where 77% of attempts to antedate references were rejected by the administrative court.

Given the difficulty of asserting invention-date-based novelty rights, it is unsurprising that applicants are more likely to assert such rights in cases of highly valuable inventions, choosing not to waste money in less valuable cases. Furthermore and perhaps contrary to conventional wisdom, my findings suggest that individual inventors assert invention-date-based novelty rights relatively less often and less successfully than large, publicly traded companies. Lastly, a practitioner survey of 1000 patent law professionals reveals, inter alia, a shared concern that attempts to antedate prior art leave patents open to challenge during litigation by providing “fodder” for validity challenges.

Keywords: Patent, first-to-file, first-to-invent, novelty, priority

Suggested Citation

Crouch, Dennis D., Is Novelty Obsolete? Chronicling the Irrelevance of the Invention Date in U.S. Patent Law (March 22, 2010). Michigan Telecommunications and Technology Law Review, Vol. 16, No. 1, 2010, University of Missouri School of Law Legal Studies Research Paper No. 2010-08, Available at SSRN:

Dennis D. Crouch (Contact Author)

University of Missouri School of Law ( email )

Missouri Avenue & Conley Avenue
Columbia, MO MO 65211
United States

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