Key Finding: In cases that reached final written decisions or were substantively denied institution, about half of the claims originally challenged in the IPR petitions were cancelled or found unpatentable. This statistic accounts for challenged claims that were denied institution for substantive reasons, as opposed to procedural reasons (e.g., time-barred). The analysis includes decisions not to institute through 2017, and final decisions through 2018, 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 final written decision (e.g., case that were settled).