2009 USPTO Reexamination Statistics

The use of ex parte reexamination proceedingscontinues to increase. Requests for reexamination are routinely granted (92% proceed to reexamination on the merits). Average pendency of ex parte proceedings is a bit over two years (median is closer to 1.5 years), which indicates that some small percentage of proceedings take much longer than two years. Of all of the ex parte reexamined patents, nearly one quarter pass through without any amendments to the claims. Eleven percent fail to certify any of the claims. The remaining majority of ex parte reexamined patents certify claims with amendments made during the ex parte reexamination process.

While inter partes reexaminations are still comparatively few in number, the rate of increase in the use of the inter partes reexamination continues, as a less costly way of challenging the validity of an issued patent than patent litigation. 95% of all inter partes reexamination requests are accepted by the USPTO. The average pendency is 3 years for inter partes proceedings (median pendency being only a bit shorter). Significantly, few patents reexamined under the inter partes proceeding escape without amending the claims, and 60% result in all of the claims being cancelled or disclaimed. The remaining patents, about one-third of the total reexamined, result in amended claims.