Patent Validity Challenges and The America Invents Act

54 Pages Posted: 24 Oct 2017 Last revised: 25 Oct 2017

See all articles by Talia Bar

Talia Bar

University of Connecticut - Department of Economics

Brendan Costello


Date Written: October 23, 2017


Patent reexamination or patent review systems can lower the cost of challenging patent validity and help improve patent quality. We empirically investigate post-grant patent validity challenges at the U.S. Patent and Trademark Office, and how the 2011 America Invents Act affected them. We compare the inter partes reexamination procedure with the inter partes review procedure that replaced it after the reform. To identify the effect of the policy changes, we exploit the fact that patents filed before the act passed, but granted after the new inter partes review system took effect, are not eligible for reexamination in the old system. We find that more patent challenges end with a patentee win after the policy change. Still, at least one patent claim is canceled in more than 60% of the cases. Litigated patents issued to small entities more often had at least one claim canceled compared to other patents.

Keywords: Inter Partes Review, Inter Partes Reexamination, Patent Validity, Administrative Adjudication, USPTO

JEL Classification: O34, K10, K23

Suggested Citation

Bar, Talia R. and Costello, Brendan, Patent Validity Challenges and The America Invents Act (October 23, 2017). Available at SSRN: or

Talia R. Bar

University of Connecticut - Department of Economics ( email )

365 Fairfield Way, U-1063
Storrs, CT 06269-1063
United States

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