Patent Validity Challenges and The America Invents Act

Abstract

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.