Determinants of Patent Quality: Evidence from Inter Partes Review Proceedings

We study the determinants of patent "quality"-the likelihood that an issued patent can survive a post-grant validity challenge. We do so by taking advantage of two recent developments in the United States patent system. First, rather than relying on the relatively small and highly selected set of patents scrutinized by courts, we study the larger and broader set of patents that have been subjected to inter partes review, a recently established administrative procedure for challenging the validity of issued patents. Second, in addition to analyzing characteristics observable on the face of challenged patents, we utilize datasets recently made available by the United States Patent and Trademark Office (USPTO) to gather detailed information about the prosecution and examination of studied patents.

We find a significant relationship between validity and a number of characteristics of a patent and its owner, prosecutor, examiner, and prosecution history. For example, patents prosecuted by large law firms, pharmaceutical patents, and patents with more words per claim are significantly more likely to survive inter partes review. On the other hand, patents obtained by small entities, patents assigned to examiners with higher allowance rates, patents with more US patent classes, and patents with higher backward citation counts are less likely to survive review. Our results reveal a number of strategies that may help applicants, patent prosecutors, and USPTO management increase the quality of issued patents.

Our findings also suggest that inter partes review is, as Congress intended, eliminating patents that appear to be of relatively low quality.