Professors Mark Lemley, Chris Cotropia, and Bhaven Sampat recently released a draft of their new article titled “Do Applicant Patent Citations Matter? Implications for the Presumption of Validity.” [Download Here.]
For the article, the trio analyzed the file histories of 1,500+ utility patents issued in 2007 and compared references used in office action rejections with the list of references cited on the patent cover-pages. The objective was to figure-out the role of applicant-cited prior-art in the examination process.
Findings: Patent examiners rarely rely on applicant-submitted prior-art when making rejections. Only 13% of the prior art used in office action rejections was applicant-submitted (despite the fact that 74% of cited references are applicant-submitted). Generally, the study found that examiners “effectively ignored” applicant-submitted prior art regardless of how few or how many references were cited; regardless of the timing of the IDS filing; and regardless of whether the submission included an EPO search reports identifying the references as “X-references.”
Implications: The authors suggest several implications of their findings: (1) That it likely does not make sense to find inequitable conduct when an applicant withholds prior art (since the art would not have been used in a rejection anyway); (2) That the presumption of validity associated with patents may be too strong; and (3) That studies based on patent citations likely lack merit.
Notes: I have privately e-mailed Professor Lemley with several comments on the article. Patent prosecutors will not likely be surprised that US examiners tend to rely on their own search results. However, I was surprised at the extent to which they found that this occurs. As a matter of patent office policy, I would think that some minor changes could alter these results. For instance, examiners should be given a tool for performing text-searches that are limited to submitted (and identified) prior art references. The office may also want to educate examiners on how to read European search/examination reports.
There are several rational reasons for examiners to cite their own prior art. Because of the backlog, PCTs, and provisional applications, US examination often begins several years after the application was originally filed. During that interim, many references become available that were not known at filing. Thus, it is not surprising that applicants rarely cite 102(e) prior art, but examiners cite loads of it. There is some reason to think that this “newer” prior art is probably better because of technological developments. It may also be true that the applicant and examiner references are cited for different purposes -- namely, applicants cite references that are generally relevant to the invention while examiners are looking for references that teach each particular element in the filed claims. A third issue is that applicants tend to modify their claims during prosecution. That modification may make their originally cited art less relevant.