USPTO inter partes proceedings are not healthy for patents. Inter partes reexamination has resulted in the cancellation of all claims of a patent nearly 45% of the time. The probability of any single claim being canceled is likely above 70%. The primary appellant from the Examiner's decision in inter partes reexamination has been the Patent Owner nearly three times as often as it has been the Challenger.

The success rate of Challengers in inter partes proceedings could be caused by a number of things, including the lower burden of proof before the PTO, the broader claim construction, and tendency of the higher-placed PTO officials to pay little deference to the decision of junior examiners. Whatever the true causes, however, it is noticeably easier to defend patent rights before a jury than it is to recover them from inter partes PTO proceedings, which is why accused infringers often make use of these proceedings.