Do US patent examiners consider applicant-submitted prior art?

What do US patent examiners do with the prior art that is submitted by the applicant?  Under U.S. law, as part of their duty of candour, applicants are obliged to submit any prior art of which at they are aware (although applicants are not under any obligation to carry out a search out for prior art). After all, a US patent examiner seems to have only a limited amount of time to search for, evaluate, and apply the prior art during the entire process of examination. In a 2001 article, Lemley estimated that an examiner devotes only about 18 hours, on the average. Moreover, the submission of prior art by the applicant plays an important role in the strong presumption of validity that a registered patent enjoys under US law. Surely, then, the examiners must be making copious use of the prior art that has been submitted by applicants.

The answer is—maybe not, at least based on a study reported in the respected journal, Research Policy, Christopher Cotropia, Mark Lemley and Bhaven Sampat, “Do applicant patent citations matter?”, 42 (2013), 844-855). (This Kat was not able to find a link to the text of the article, but there is a version of the article that is available for Kat readers on, here.) The authors found, to their surprise”, that “[p]atent examiners generally do not rely on what would appear to be the most promising source of prior art: information submitted by the applicants themselves.”

Stated more comprehensively:
… [P]atent examiners did not use applicant-submitted art in the rejections that narrowed claims before these patents issued, relying almost exclusively on prior art they find themselves. This is not simply because the applicants have “drafted around” the art they submitted. Even late-submitted art is not commonly used by examiners in their rejections. Nor does the examination appear to be that applicant art is uniformly weak. We also provide evidence suggesting examiners are less likely to use prior art discovered by foreign search authorities for the same invention, art that is presumably of better than average quality and relevance.
As such, the authors go on to observe:
“Our findings have potential implications for policy initiatives that aim to improve patent quality through bringing more ‘prior art’ before examiners, under the theory that with better access to prior art they would be less likely to issue patents of questionable validity.”
Regarding the basic finding, namely that examiners rely on the results of their own searches, the study concluded that 98% of applicant-submitted citations of US patents are not used by examiners in rejections. Instead, more than 90% of the US patents that are relied upon by examiners in rejections derive from patent searches carried out by the examiner. Moreover, examiners used only 2.9% of citations of foreign patents submitted by applicants, and even less applicant-submitted non-patent art, namely 1.1%, in rejections.

And so, the question: how do we account for the apparent fact that US examiners are making only very limited use of applicant-submitted prior art; instead, they rely on their own search results. The authors reject the claim that examiners do so because applicant-submitted art is of lower quality. Instead, the authors focus on two possibilities: either the examiners are acting in an efficient, time-saving manner in relying on their own searches, given the time constraints to read and analyse the prior art submitted by the applicants (especially in light of claims that applicants sometimes tend to “flood” the examiner with prior art) or the examiners are evidencing what it is called the “myopia effect”, namely that examiners prefer to rely on the art they find as opposed to what the applicants provide. The authors opt for the second explanation: “[T]here is literature suggesting that people tend to think more highly of things they do themselves than things others provide to them ”, relying on an article by Buccafusco and Sprigman, “Valuing intellectual property: an experiment”, Cornell Law Review 2012.

This Kat appreciates that behavioural economics is all the rage, here, and that the “myopia effect” would seem to fit within this empirical approach to the social sciences. Indeed, the “myopia effect” might explain the basic finding of the study, namely that US examiners do not use the prior art submitted by applicants. But more empirical work is needed. For the moment, the empirical rigour that undergirds the research method of the study does not extend to the explanation for the behaviour observed.Perhaps this will be the subject focus for a further study. Be that as it may, the current research does offer much food for thought on the way that applicant-submitted prior art impacts on the examination process, at least in the US.
Do US patent examiners consider applicant-submitted prior art? Do US patent examiners consider applicant-submitted prior art? Reviewed by Neil Wilkof on Tuesday, June 17, 2014 Rating: 5


  1. This is a myth: "Moreover, the submission of prior art by the applicant plays an important role in the strong presumption of validity that a registered patent enjoys under US law"

    Sounds good but just not linked to reality. Applicants are not charged with examination (of any kind) and it is the function of examination that earns the presumption of validity. Examiners examine and applicants invent.

    Your premise then, your foundation lacks the vigor to support your conclusion.

  2. Applicants submit all the art they are aware of 'out of an abundance of caution' the vast majority of which is therefore likely to be irrelevant. A US decision a few years ago caused the paranoid to submit even more art, including the instruction manual for their kitchen sink. If the submitted art is a published patent application or a an article from a journal on their databases (anyone have a link to a list of their sources?), chances are the examiner will have found it themselves.

  3. From my own experience of prosecuting US cases the myopia effect may be happening. US Examiners are more likely to take their own idiosyncratic approach (in comparison to other Examiners around the world on the same case) and will focus on particular prior art, even when more relevant documents are submitted later. I can imagine that once an Examiner has constructed their objections based on certain prior art they found, they are reluctant to abandon that position and start again with other documents.

  4. I recall a warning letter to the CIPA journal some years ago reporting that a US patent prosecuted by the writer had been lost for lack of disclosure of prior art cited in the corresponding GB application. The undisclosed document was the GB equivalent of a US patent that had been cited by the examiner in the US prosecution. The writer had not notified the GB equivalent as its disclosure was identical with the cited US patent.

  5. New art = new grounds for rejction = one more step from finality = one more step to reaching the "count".

    It is hardly surprising that the examiner avoids making extra work for themself.

  6. Very interesting! Given the high percentage of none prior art readers at the USPTO, it would be great to to able to remove this section of the patent, as it would save clients substantial attorney's fees.

  7. Megan,

    Why on earth do you think this section incurs substantial attorney's fees?

    This section is NOT a "required reading" mandate, and the attorney is acting merely as a compiler of that which is already known.

    If you are seeing substantial attorney's fees for this, you need to challenge your billings.

  8. US examiners at least tick the docs on the IDS form, EPO examiners even forget to put a D in the search report when citing the acknowledged prior art as A document in search reports...

  9. You may not be comparing like with like here. If the applicant has acknowledged some prior art in the description, then the assumption is that he/she does not intend to cover this by the claims, and so the claims are interpreted, if possible, with the presumption that they don't cover it, however much they may appear to. Whereas with a piece of prior art which is not acknowledged, such as one the examiner has found in the search, there is no such presumption. With such a piece of prior art, the examiner can say "It's been done before" whereas with acknowledged prior art the examiner should normally be saying "You've got the claims wrong here".

  10. Anonymous @ 22:48.

    The discussion here is NOT about art that is cited (or discussed) in the body of the application - be it in the old "Background of the Invention" section - or elsewhere.

    Rather, this discussion is on art supplied in and IDS, of which, the applicant is EXPLICITLY making no affirmative statement of patentability over. This is simply NOT the applicant's job or role - it cannot be stressed enough that it is SOLELY the role of the examiner to examine. See Taffas.

  11. Several comments made by people having ZERO experience of patent prosecution, at least in the US.

    Before being critical of US examiners ignoring art to meet their 'count' let's take a good look at the rubbish the EPO have been granting for the past few years. I used to see a granted US patent with arguably overly-broad claims, to confidently find that the corresponding EP application was either granted with a more reasonable scope or was still under examination with the objections against the broad claims. Today, the situation is reversed. I deal with pharmaceutical patents.


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