The Analogous Art Doctrine Post-KSR: Insights from the Federal Circuit’s Daedalus Decision

by Dennis Crouch
In a short nonprecedential decision, the Federal Circuit affirmed a PTAB IPR decision finding claims 15-25 of U.S. Patent No. 8,671,132 (‘132 patent) unpatentable under 35 U.S.C. § 103 over combinations of prior art references. Daedalus Blue LLC v. Vidal , No. 2023-1313, slip op. at 2 (Fed. Cir. Mar. 13, 2024) .  The key issue on appeal was whether the Gelb reference qualified as analogous art for the purposes of the obviousness analysis.  Daedalus unsuccessfully argued that the PTAB erred in two respects: (1) by finding Gelb to be in the same field of endeavor as the ‘132 patent, and (2) by determining that Gelb is reasonably pertinent to the problems addressed by the ‘132 patent.  This post discusses the analogous arts test and provides key guidance to patent attorneys in today’s post-AIA world.

The law of analogous art is a critical concept in determining the obviousness of an invention under 35 U.S.C. § 103. Even if a reference qualifies as prior art under Section 102, it can only be relied upon for an obviousness rejection if it is considered “analogous” to the invention at issue.
To be considered analogous art, a reference must either be (1) from the same field of endeavor as the claimed invention or (2) reasonably pertinent to the particular problem addressed by the inventor, regardless of the field in which that reference was working. In re Bigio , 381 F.3d 1320 (Fed. Cir. 2004). The “field of endeavor” inquiry focuses on the broad scope of the field and not the specific problem being solved. In re Deminski , 796 F.2d 436 (Fed. Cir. 1986). On the other hand, a reference is “reasonably pertinent” if, even though it may be in a different field from that of the inventor’s endeavor, it is one which, because of the matter with which it deals, logically would have commended itself to an inventor’s attention in considering his problem. In re Clay , 966 F.2d 656 (Fed. Cir. 1992). Importantly, a reference need only be either in the same field of endeavor or reasonably pertinent to the problem—it need not satisfy both criteria to qualify as analogous art. Donner Tech., LLC v. Pro Stage Gear, LLC , 979 F.3d 1353 (Fed. Cir. 2020).
While the Federal Circuit has maintained the traditional two-prong test for determining analogous art post- KSR , the court’s decisions suggest a trend towards a more expansive and flexible approach. In Wyers v. Master Lock Co. , the Federal Circuit noted that the Supreme Court’s decision in KSR “directed us to construe the scope of analogous art broadly.” 616 F.3d 1231 (Fed. Cir. 2010). Similarly, in Airbus S.A.S. v. Firepass Corp. , the Federal Circuit emphasized that the analogous arts inquiry “should take into account any relevant evidence in the record cited by the parties to demonstrate the knowledge and perspective of a person of ordinary skill in the art.” 941 F.3d 1374 (Fed. Cir. 2019).
Patentees also have tools at their disposal to potentially narrow the scope of analogous art. As seen in Netflix, Inc. v. DivX, LLC , explicitly articulating the problem solved by the invention (perhaps within the patent claims themselves) can limit the field of endeavor and pertinent prior art to references addressing that particular problem. 80 F.4th 1352 (Fed. Cir. 2023). Thus, while the overall trend post- KSR may be towards a more flexible analogous arts test, strategic patent drafting can still play a role in circumscribing the applicable prior art.
The ‘132 patent, owned by appellant Daedalus, relates to a policy-based data management system for handling files.  Regarding the field of endeavor, the Federal Circuit noted that it need not reach this issue, as the PTAB’s finding that Gelb was reasonably pertinent to the problems of the ‘132 patent was sufficient on its own to establish Gelb as analogous art. *Id.* at 4. A reference qualifies as analogous art if it is either “in the same field of endeavor” or “reasonably pertinent to the particular problem with which the inventor is involved.” Donner Tech., LLC v. Pro Stage Gear, LLC , 979 F.3d 1353 (Fed. Cir. 2020).
The ‘132 patent , owned by appellant Daedalus, relates to a policy-based data management system for handling files. In its short opinion, the Federal Circuit did not reach the “field of endeavor” question because it concluded that Gelb was reasonably pertinent to the problems of the ‘132 patent.   In particular, the court concluded that the ‘132 patent identified the problem that prior art systems did not “permit a user to automatically select between multiple storage options” or address “files with varying storage or performance requirements or equipment with varying capacities and performance levels.”  The PTAB found that Gelb addresses the same problem – i.e., prior art storage access methods did not allow programmers to write code enabling users to automatically select appropriate storage devices based on high-level concepts like data sets and databases.  On appeal, the Federal Circuit agreed that substantial evidence supported this PTAB determination.
Although the Daedalus patent focuses on a networked environment, the claims did not expressly require the networked environment. The patentee particularly argued that under a proper claim construction that Gelb was not analogous because that reference focused on a non-network environment.  Kevin McNish, arguing for the patentee made the case at oral argument:
When we’re talking about a distributed system, we’re talking about multiple machines, and these machines are processing instructions, capable of processing instructions, capable of functioning as part of the distributed system or autonomously as well. Contrast that to what we have in Gelb, where, again, we just have these peripheral devices, these being hooked up directly by cables into this centralized single-machine architecture. . . .
So ultimately, what this comes down to is, you know, Gelb, again, single machine, non-networked, centralized architecture, not pertinent to problems in multi-machine networked distributed storage systems in which the invention operates, as reflected by our construction of plurality of clients, as clients in a networked environment.
On appeal, the Federal Circuit rejected this claim construction argument that the term “plurality of clients” should be limited to “clients in a networked environment.” Even under Daedalus’s proposed construction, the court explained, the PTAB’s reasonable pertinence finding would stand, as the storage selection problem identified in the specification was agnostic to whether the clients are networked.  Arguing on behalf of the USPTO, Michael Forman explained the USPTO’s position as follows:
I think if you look at both the specification of the 132 patent and the prosecution history, you can see that the patentee was defining the problem as a data management problem, not as a network problem.
The Federal Circuit agreed with this perspective, that the problem stated was not focused on network issues.  In other words, the patentee’s argument might have worked if the Daedalus patent had expressly identified the problem being solved as focused on storage options “in a networked environment.”
Although the patentee lost this appeal, I believe that it adds to the body of evidence that applicants should consider filing narrower patent specifications when appropriate. In our post-AIA world, patents are more likely than ever to be invalidated post-issuance, and a carefully crafted problem statement can help limit the scope of analogous art. By explicitly identifying the specific problem solved by the invention, particularly in the broadest claims, applicants may be able to circumscribe the universe of prior art that can be relied upon for obviousness. While this approach requires striking a delicate balance to avoid unduly restricting claim scope, it is a strategy worth considering in light of the evolving analogous art doctrine.
Key Takeaways for Patent Prosecutors:

Recognize that the AIA changed the post-grant rules.  Today protecting against post-grant obviousness cancellation is often just as important as avoiding narrowing constructions that might hurt the infringement case.
In appropriate cases consider explicitly stating the problem solved: Clearly articulating a specific problem addressed by the invention in the specification and claims can potentially limit the scope of analogous art relied upon by the examiner as well as by the PTAB in a post-grant trial.
Consider two separate patent families filed concurrently: one with a broad statement of the problem and another with a narrower construction.

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The Donner Tech case includes an interesting footnote that was not contemplated by this decision.
One exception that has been contemplated, but not solidified, by our case law is where the problem a reference solves is so specific to its particular field of endeavor that a PHOSITA could not possibly describe the problem the reference solves other than in a manner that rules out all art outside that field.
Citing Sci. Plastic Prods., Inc. v. Biotage AB , 766 F.3d 1355, 1360 (Fed. Cir. 2014).