In 2006, PTO relations with the patent bar were near nadir because of a proposed set of rules that would radically change the practice of filing continuation applications. Although patent attorneys generally avoid public comment, the continuation proposal led to several hundred public submissions.(n1)
Many of the comments argued that continuations only play a minimal role in increasing pendency. Using a sample of 10,000 recently issued patents, I wanted to see whether the technology areas with the largest pendency are flooded with continuation applications. A strong correlation would indicate that the PTO was correct in its assessment that continuations are a major cause of the 'pendency crisis.'
For each technology classification, I calculated two primary statistics: (1) the average pendency of the issued patents (months from filing the application until issuance) and (2) the prevalence of continuations (as measured by the percentage of issued patents that had either one or more non-provisional parent or multiple provisional parents).
As it turns out, there does not appear to be much correlation at all.(n2) The lack of correlation is exemplified when looking at the technology areas on the extremes. For instance, there is no overlap between the top-ten-percent of classes with the highest pendency and the top-ten-percent of classes with the highest prevalence of continuations.
As can be seen in the linked Google Spreadsheet, technology areas of chemistry and drugs have the highest rates of patenting continuations. For those areas, over half of the issued patents are continuations.
- Spreadsheet of Results
- Cite as Dennis Crouch, "Prosecution Data: Continuations," Patently-O, February 23, 2007.
- n1: At this point, the rules have neither been implemented nor discarded.
- n2: I suspect that with a larger sample size, a small but statistically positive correlation would be identified.