Key Finding: In cases that reached final written decisions or were substantively denied institution, about 54% of claims that were originally challenged in the IPR petitions were cancelled or found unpatentable. This statistic accounts for challenged claims which were denied institution for substantive reasons, as opposed to procedural reasons (e.g., time-barred). The analysis includes decisions not to institute through 2015, and final decisions through 2016, due to the temporal relationship between these types of decisions. Specifically, final decisions typically issue about one year after the institution decisions. Accounting for that one year differential avoids an improper skewing toward the outcomes of decisions not to institute. This analysis does not factor in challenges that did not reach a decision on the merits because of settlement.