All Citations Are Not the Same – Exploring Examiner Citations from US Patent Documents – Part 1 – An Introduction

Patent documents from the United States have a number of different types of citations associated with them. Occasionally, citations are embedded into the specification of the document itself, but normally the majority of the citations are communicated between the examiner and the applicant via forms 892 and SB08. Form SB08 is better known as the Information Disclosure Statement (IDS) and is used by the applicant to communicate the prior art references that they are aware of. According to 37 C.F.R. 1.56, entitled Duty to disclose information material to patentability, applicants for US patents have a duty of disclosure, candor and good faith to notify the Office of these references. The Manual of Patent Examining Procedures (MPEP) provides the following guidance in this regard:

The Office encourages applicants to carefully examine:

  • Prior art cited in search reports of a foreign patent office in a counterpart application
  • The closest information over which individuals associated with the filing or prosecution of a patent application believe any pending claim patentably defines, to make sure that any material information contained therein is disclosed to the Office.

Ordinarily, in the case history or file wrapper, the IDS is accompanied by Form 1449, the List of References cited by applicant and considered by the examiner. Form 1449 is typically a copy of the IDS where the examiner puts their initials next to the references they have reviewed. In practice, this usually takes the shape of the examiner placing their initial next to the reference at the top of the page and then drawing a line down to the bottom of the page, signifying that all of the documents on the page were considered. As you might imagine, Form 1449s are normally not terribly interesting in, and of, themselves.

The Office requires the applicants to provide the “closest information” but for a variety of reasons the list of references provided by applicants on an IDS can sometimes be quite lengthy and some commentators have questioned how relevant some of these citations are to the case at hand and whether the examiner really considers them during the case. Considering all citations can still be a valuable exercise for exploring the development of a technology but analysts should still consider the source.

Form 892, on the other hand, is referred to as the List of References cited by examiner. This is the list of references identified during the examination process and represents the prior art used for the various office actions that take place during prosecution. These references can lead to rejections of various claims within an office action or they can simply be mentioned as being “made of record, but not considered”. In all cases, citations on Form 892 are hand-picked by the examiner, based on their relevance to the application at hand, and can be considered to be highly likely to be on the same topic as the case.

All of these forms can be found by referring to the Display References tab when looking at a case in US Public PAIR. Alternatively, when looking at the front page of US granted patents in the Cited References section, the examiner citations are marked with an asterisk (*) to distinguish them from the references disclosed by the applicant on the IDS.

The United States is reasonably unique, with its duty of disclosure, since most other patenting authorities don’t require applicants to disclose known prior art references. The office actions and search reports associated with these non-US patent applications only contain the examiner references by default and so the situation where examiner citations need to be sorted out from applicant citations doesn’t exist.

Now that the source of citations associated with US patent documents have been identified it is appropriate to discuss the concept of forward and backward citations. Any discussion of patent citations begins with a root document. The references that the root document cites or references itself are referred to as backward citations, since they are references which proceeded, or were published before, the root document. Conversely, going forward in time from the root document, any more recent document which references the root document are referred to as a forward citation for the root document. In the subsequent examples, given in future posts, a portfolio of root documents will be selected and the corresponding forward citations to these documents will be examined.

Over the past decade the US has moved from a point where, initially, there were no asterisks and no electronic file wrappers with a Display References tab, so citations from the examiner or the applicant could not be distinguished from one another without looking at the file wrapper by hand. Needless to say, trying to distinguish examiner from applicant citations under those circumstances was nearly impossible and so it simply wasn’t done unless it was absolutely imperative to do so, say for litigation. The situation is much better today, where citations can be filtered or searched for, by whether they came from the examiner or the applicant and the source of the citation can be seen in most database records showing the citation data. Having said this, it still takes a little work to differentiate examiner citations on US patent documents. Based on the higher likelihood of relevance associated with the hand-picked examiner citations it can be valuable to consider separating them during the course of conducting a citation analysis. Most citation studies on US patent documents, to date, have not considered the source of the citation but with current databases and techniques it is now possible to do so. In subsequent posts on this topic a specific example will be used to demonstrate how US examiner citations can be separated from ones coming from the applicants. A discussion of third-party services that have collected, and converted Public PAIR data into computer-readable text will also be covered. These services have launched only recently and details on how they can assist provide additional perspectives on this task will be discussed.

Comments 6

  1. Thank you Rubal. I hope the wait wasn’t too bad since the follow-up post has already been published.

  2. This is very informative, I just looked through Patr-2, was fascinated and thought I would go back and give Part-1 a look too… Citation and more importantly co-citation analysis is an extremely powerful tool that I think does not get nearly enough attention by the average practitioner. Cheers & thank you for sharing…

    1. Hello Thomas,

      I am happy you enjoyed the post. There will be one or two additional ones on some further nuances.

      Thanks,
      Tony

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