How to Avoid Self-Inflicted Wounds (Applicant Admitted Prior Art) in Your Patent Applications

When drafting their patent applications, many inventors have an instinct to gratuitously describe what others have developed before them. Understandably, they want to give credit where credit is due! 

That’s acceptable and sometimes even necessary in other contexts, especially in a setting where you need to show continuity with other work in your field. For example, when you’re submitting a manuscript for publication in a journal, you may have to appease peer reviewers and acknowledge other work in the same field.

But it’s not good practice—and can often be harmful—in a patent application. Why? Because an examiner will be evaluating whether your invention is obvious, and the examiner can use your own statements about prior work against you.

During the process of negotiating your patent application with the patent office, if you (the patent applicant) make a statement on the record that identifies somebody else’s work as prior art, your own statement could prevent you from getting a patent.

In the patent world, this pitfall is known as “applicant admitted prior art” (sometimes abbreviated as AAPA). Let’s take a closer look at what it entails, and what you can do to avoid making such admissions.

What is Applicant Admitted Prior Art (AAPA)?

The USPTO formally defines AAPA as follows:

A statement by an applicant in the specification or made during prosecution identifying the work of another as “prior art” is an admission which can be relied upon for both anticipation and obviousness determinations, regardless of whether the admitted prior art would otherwise qualify as prior art under the statutory categories of 35 U.S.C. 102.

In simple terms, what that means is: Anything that you (the applicant) say is prior art can be used against your application as prior art — even if that work would not otherwise be considered prior art.

What Constitutes an Admission of Prior Art?

There are lots of ways that an applicant could inadvertently create AAPA. Broadly though, there are four main types of admissions:

1. Admitting that a reference is prior art
2. Characterizing a reference as prior art: A “characterization” refers to what you believe the reference teaches. The statement can be used against you so long as it’s reasonable — even if it’s not fully accurate.
3. Non-reference admitted prior art: A “non-reference” means that, outside of your admission, there is no source for the prior art.
4. Admitting that something is obvious: This may include acknowledging a source as analogous art, or admitting that a modification to known prior art is obvious.

How Might the Examiner Determine That I’ve Made an Admission of Prior Art?

Rather obviously, anything labeled “prior art” in the patent application or the applicant files will be treated as an admission.

But you do not need to use the words “prior art” to make an admission. Anything described using words like “conventional”, “known”, “previous”, and “past” may be considered a presumptive admission.

Even subtle statements may constitute AAPA. For example, in the case of In re LoPresti, the applicant didn’t use the words “prior art” in connection with the Craggs and McCann patent. However, because of the way the applicant disclosed the Craggs and McCann invention, the court ultimately determined that the admission was prior art.

AAPA may also include anything described in the “background” section of the patent application. This is not a settled point in case law; no case has explicitly addressed whether the entire background section may be treated as a per se admission. But cases like LoPresti make it likely that, at minimum, every reference in the background section can be treated as an admission.

Can My Own Patents and Applications Be Construed As AAPA?

The short answer: It depends.

When you file a new patent application, your company’s previously filed applications may be considered prior art against your new invention — unless the information falls under one of two specific exceptions provided by the America Invents Act.

The subject is pretty complicated, which is why we’ve dedicated an entire separate blog post to unpacking it. Patent nerds, this way please!

AAPA in Recent USPTO Guidance

I cited some older case law in the discussion above, but AAPA remains a real patent pitfall even today, as illustrated by the updated guidance issued by the Director of the U.S. Patent & Trademark Office (USPTO) in 2022, and the Director’s 2023 review of a PTAB decision.

In 2022, USPTO Director Vidal issued updated guidance on the topic of AAPA, stating:

[AAPA] are permissible evidence in an inter partes review for establishing the background knowledge possessed by a person of ordinary skill in the art and provide a factual foundation as to what a skilled artisan would have known at the time of invention.

The 2022 guidance goes on to explain that AAPA can be used for a variety of purposes when challenging a patent: (1) to “supply missing claim limitations that were generally known” in the prior art prior, (2) to “support a motivation to combine particular disclosures”; (3) to “demonstrate the knowledge of” a person of ordinary skill in the art; and (4) “for any other purpose related to patentability.”

Subsequently in 2023, Director Vidal issued a review of a PTAB decision, in which she cited the 2022 guidance and approved the PTAB’s reliance on AAPA in a patent challenge.

Mentioning Prior Art in Your Patent Applications

Discussing the prior art in your patent application can be risky: You might prevent yourself from getting an issued patent if your application contains an imprecise or uninformed statement about prior art, or if your statement about prior art gets misinterpreted.

For this reason, you should not say anything about the prior art in your patent application unless you have a very good reason to say it. And when you do refer to prior art, you need to be absolutely certain that your statement is accurate.

Mentioning Prior Art in the Specification

There are a few good reasons that you might want to reference prior art in the specification of your patent application. Here are a couple:

• To explain how the invention improves on some specific conventional technology
• To explain the advantages of the invention compared to some specific existing technology

However, you should not do the following in the specification:

• Disparage the prior art: There’s no benefit to describing the deficiencies in prior art systems. Instead, consider framing the same information as an advantage of the invention.
  • DON’T say: The widgets on the market today suffer from high friction and low efficiency.
  • DO say: The example widget shown in Figure 1 [of the patent application] can be made to have low friction and high efficiency, for example, compared to at least some conventional widgets. 
• Say what’s missing in the prior art: If the examiner finds something that you said was “missing”, you’ll lose credibility, which may increase your chances of a rejection.
  • DON’T say: None of the widgets on the market today has a flux-capacitor.
  • DO say: The example widget shown in Figure 1 [of the patent application] has a flux-capacitor.
• Describe how your invention builds on conventional technology: This makes your invention sound obvious.

What About the Background or Detailed Description of My Patent Application?

Where possible, you should avoid mentioning the prior art in the background and detailed description.

There’s generally no benefit to describing the references in your patent application. The proper way to disclose prior art to the USPTO is through an information disclosure statement, which lists each reference that you want the examiner to consider. If you do that, you’ve met your duty of candor and good faith.

And if/when you do need to persuade the examiner that the claimed inventions are patentable over the prior art, the background and detailed description are not the right avenues to do so. Keep in mind that examiners are primarily assessing your claims and drawings, and when they refer to the background and detailed description, it’s usually in brief — only for context.

You should also avoid describing the problem that your invention solves in the background section. Instead, you should describe the problem in the detailed description section of the patent application. In many cases, a significant part of the inventive process is identifying the problem to be solved. If you describe that in the background section, the examiner might say that makes it AAPA, and then say the invention is obvious because the problem was well-known. 

Mentioning Prior Art in Office Action Responses

When dealing with the patent office to obtain patent protection, the right time to provide written arguments relating to specific prior art references is only after the patent examiner has made a rejection citing that specific prior art reference — in other words, in an office action response.

When there’s a particularly close prior art reference, you may also wish to address that reference in order to reduce your exposure to IPR challenges based on that reference.

Avoid Unexpected Prior Art Pitfalls

Crafting high-quality patent applications is a very technical endeavor, and partnering with a skilled attorney can help you to avoid making accidental admissions in your patent applications.

Prior art remains one of the top reasons why the USPTO rejects patent claims — and the topic extends far beyond AAPA. Get our best tips on how to avoid common prior art obstacles by downloading our FREE eBook today!