Don’t Let the USPTO Get Away with Speculating that a Feature of an Invention is Obvious

One of the most frustrating fact patterns an applicant or patent attorney can face is when you are up against an examiner who thinks everything is obvious. 

This feature – obvious.  That feature – obvious. Everything in the application – obvious.  Even when the Examiner does not have sufficient evidence to back up these assertions.

You set forth a reasonable amendment to the claims, and the Examiner interprets the prior art as somehow teaching or suggesting the new feature.  Even when there is no inkling in the prior art of such features.

You interview with the Examiner to bounce around possible amendments, and the Examiner says things like “well, one of skill in the art would understand that it is within the scope of this prior art reference.”

Or: “yeah, but I think that change would have been obvious.”

We have all been there.  The Examiner thinks a claimed feature of an invention is obvious, and wants you to keep narrowing the claims until they are worthless.  Don’t do it.  Appeal.  There is case law to help you.

Here is a quote that I have used successfully a number of times on appeal:

The Patent Office has the initial duty of supplying the factual basis for its rejection. It may not, because it may doubt that the invention is patentable, resort to speculation, unfounded assumptions or hindsight reconstruction to supply deficiencies in its factual basis.  In re Warner, 379 F.2d 1011, 1017 (CCPA 1967)( emphasis in original).

This case is over 50 years old, but it gets the job done.  If you can get the PTAB to mention this quote in an appeal decision, you have a 82.9% chance of the PTAB reversing the rejection, as shown below by data from PatentAdvisor.


I did a search in PatentAdvisor of Appeal Briefs I have filed since 2017, and as shown below, I have used this case in ex parte Appeal Briefs before the PTAB in 28 appeals in 24 different applications. My record is 27-1 in these Appeal Briefs.

I pick and choose my battles carefully, so don’t think you can win every appeal with it, but don’t sleep on In re Warner. It is a strong arrow to have in your quiver.

Of course, knowing how the PTAB uses In re Warner is of tremendous value.

The PTAB will not let an examiner formulate speculative definitions

A 2022 PTAB decision Ex parte Weiss, Appeal 2022-00941 is a great example of an examiner speculating.  In this case, the claim recited “the particles of said dispersed catalyst have a size between 10 and 150 microns.”   The Examiner relied on a reference teaching a “nano-dispersed hydrogenation catalyst” that contains particles of “micronic” dimensions and/or “sub-micronic” dimensions.  Based on this teaching, the Examiner asserted that the particles could be solely micronic, and these “‘micronic’ dimensions would be reasonable units of measure in the ranges of approximately .001-1000 microns” (emphasis added), which would read on the claimed range of 10 and 150 microns.    

The PTAB shot down these assertions by the Examiner as lacking a factual basis, finding that the Examiner’s definition of “micronic” was not supported by evidence, and that the terminology “nano-dispersed” undermined this definition. The PTAB, citing In re Warner, concluded that “it is speculative at best to assert that Rispoli’s ‘micronic’ particles overlap with the claimed range of 10-150 microns.”

The Examiner’s assertions about what “would be reasonable” were in my opinion a red flag indicating that the Examiner’s rejection was based on speculation.  Watch out for this language.  Unless the Examiner’s comments are directed to something that is indisputable, challenge them as being speculative.

The PTAB will not let an examiner read features into the drawings

Another recent decision Ex parte Blumenthal, Appeal 2022-003190 (PTAB Jan. 2023) illustrates how to deal with an examiner who is asserting that something is depicted in the drawings without any evidentiary support.

The claims recited “at least one shoulder of the set of shoulders extends an arcuate distance of at least 20 degrees with respect to the first axis,” while prior art figure showed this:

The Examiner cited teeth 1033 as being the claimed “shoulders” and asserted that “there are 12 shoulders, and . . . 360 degrees divided by 12 is 30 degrees, which is considerably more than the claimed 20 degrees or more.”  When the Appellant pointed out that the Examiner’s math was wrong due to the presence of gaps between the teeth 1033, the Examiner asserted that each “gap is small, so the teeth are at least 20 degrees.”  

The PTAB smacked down this reasoning:

The Examiner’s finding appears to be based entirely on speculative assumptions regarding the relative proportions of each widened tooth 1033 and the gap between adjacent teeth, as depicted in Figure 6. Such speculation is insufficient to support an obviousness conclusion. See In re Warner, 379 F.2d 1011, 1017 (CCPA 1967) (holding that rejections based on obviousness “must rest on a factual basis” and may not “resort to speculation, unfounded assumptions, or hindsight reconstruction to supply deficiencies in [the] factual basis”).

In conclusion, if you think the Examiner is reading too much into the disclosure of a reference, do not simply amend the claims to appease the Examiner.  Hold the Examiner to a higher standard of examination, a standard that the PTAB will demand.  Call out speculation and unfounded assumptions on appeal.

One thought on “Don’t Let the USPTO Get Away with Speculating that a Feature of an Invention is Obvious

  1. “Obviousness” is the last refuge of scoundrel Examiners. It is easy for them to wave their arms and say obvious (in combination with art destroying the function of the primary reference). Then, they can get points toward their quota. It is sad Examiners are motivated to waste time.

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