According to some practitioners, this is a good strategy to force the Examiner to provide a reference, because Examiners don't want to be bothered with an affidavit. Since I'm as annoyed as the next guy by allegations that elements are "known", "well-known," "notoriously well-known," and "extremely well known," I was curious to know a) the legal basis for the demand for an affidavit and b) whether or not it's a good way to force the Examiner to provide a reference.
37 CFR 1.104(d)(2) really does say that the Examiner must provide an affidavit when relying on personal knowledge:
When a rejection in an application is based on facts within the personal knowledge of an employee of the Office, the data shall be as specific as possible, and the reference must be supported, when called for by the applicant, by the affidavit of such employee, and such affidavit shall be subject to contradiction or explanation by the affidavits of the applicant and other persons.I found a few instances where this "personal knowledge" issue has been raised at the BPAI. Only one of these Board decisions said that the Examiner should have provided an affidavit, and in this one the Examiner really did state that the element came from "facts within his personal knowledge". The other cases were found to be instances of Official Notice, and in most of them the Examiner made the Official Notice explicit.
Takeaway: The rules for traversing Official Notice are very specific, and not doing so properly is an admission that the element is known. So, instead of arguing "Examiner didn't provide a reference, so must have been relying on personal knowledge," it seems much more productive to instead assume that the Examiner is invoking Official Notice when no reference is provided, and to properly traverse the Official Notice. Sure, there are decisions where the Board treated the real issue as Official Notice rather than personal knowledge, and didn't punish the Applicant for not properly traversing — but why rely on the Board's generosity?
Here's a Summary of the Board's findings on the "personal knowledge" issue.
Ex parte Hull: The Examiner really did use personal knowledge! The final Office Action said: "The examiner has personal knowledge...In September, 1998, the examiner cut hyperlinks from a web browser and pasted said hyperlinks into an email. While composing an email message in Microsoft Outlook within the Windows operating environment, the examiner cut URLs of online documents from Internet Explorer and pasted them into said email message. Thus, the limitation of Claim 59 reads on this personal knowledge of the examiner." The Applicant argued that it was improper to reject a claim based on personal knowledge. The Board found in favor of the Applicant: "Therefore, we decline to consider the examiner’s personal knowledge as evidence because the examiner has failed to provide an affidavit or declaration setting forth specific factual statements with an explanation to support the finding of record."
Ex parte Trans Texas Holding Corp.: The Examiner didn't use the magic words "Official Notice" but the Board read it that way. The first Office Action alleged that "the deposit account being secured by property of the institution" was "implicit" in the reference "because this was a well-known method of running a bank." The Applicant responded by disagreeing that this was well-known, referencing the "personal affidavit" rule, and requesting that the PTO "make of record whatever evidence it might have in this regard." The Board found that the request for a personal affidavit "is clearly inappropriate because the examiner is relying not on personal knowledge but on the general knowledge of persons having ordinary skill in the banking art that it was standard practice to provide security for deposit accounts."
Ex parte Duck: The Examiner asserted that a feature was "well-known" instead of using the magic words "Official Notice." The Applicant argued that the examiner did not provide either a reference or a personal affidavit in support of this assertion. The Board didn't comment on the appropriateness of an affidavit, but did find that the Examiner's assertion was based on speculation "and thus fails to provide sufficient reasons for finding [the claim to be] obvious." [My take on this: the problem wasn't the lack of an affidavit, it was the type of facts that the Examiner was asserting to be well-known.]
Ex parte Moitra: The first Office Action said: "The Examiner takes official Notice that is is old and well-known in the art to track costs." The Applicant responded by arguing that the Examiner had cited no source for this finding, and alleged that the "Examiner states that this comes from his personal knowledge." The Board found that the requirement for a personal affidavit was inapplicable, because "this section only requires that facts that are within the personal knowledge of the Examiner be supported. The facts taken under Official Notice here were explicitly found to be common knowledge, and were not based on the Examiner’s personal knowledge."
Ex parte Trajkovic: The Examiner took Official Notice that it was well known in the art that windows are represented on the taskbar by icons and that windows were reactivated by activating these icons. The Applicant argued that the Examiner was required to submit a reference or a personal affidavit to establish facts within personal knowledge. The Board found that:
The use of status buttons on the taskbar (or status bar) in a windows environment to represent windows was so notoriously well known that it cannot be seriously in dispute (although it always would be better for an Examiner to provide a reference where it would be easily available). Such status buttons change appearance to indicate the active window and it was well known to reactivate an inactive window by activating a status button. Anyone who used a computer with Microsoft Windows before 2002 would know these facts.