Since its enactment under the 2011 America Invents Act (AIA), inter partes review (IPR) has remained a pivotal tool for challenging the validity of patents. IPR was introduced under the AIA's initiative to improve the quality of the patent system and reduce the cost of challenging and invalidating bad patents. IPR is a trial proceeding held before the U.S. Patent and Trademark Office's (USPTO) Patent Trial and Appeals Board (PTAB) through which a third party can petition to challenge the validity of a patent.