Key Finding: In cases that reached final written decisions or were substantively denied institution, about 60% 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 2014, and final decisions through 2015, due to the temporal relationship between these types of decisions. Specifically, final decisions typically issue about one year after the decisions to institute. Accounting for that one year differential avoids an improper skewing toward the outcomes of decisions not to institute. Of the claims that did not survive review, 11.3% of challenged claims were cancelled by patent owners. This analysis does not factor in challenges that did not reach a decision on the merits because of settlement.