MPEP 2141.01(a)
Analogous and Nonanalogous Art

Ninth Edition of the MPEP, Revision 07.2022, Last Revised in February 2023

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2141.01(a)    Analogous and Nonanalogous Art [R-07.2022]

[Editor Note: This MPEP section is applicable to all applications. For applications subject to the first inventor to file (FITF) provisions of the AIA, the relevant time is "before the effective filing date of the claimed invention". For applications subject to pre-AIA 35 U.S.C. 102, the relevant time is "at the time of the invention". Phillips v. AWH Corp., 415 F.3d 1303, 1313, 75 USPQ2d 1321, 1326 (Fed. Cir. 2005). See also MPEP § 2150 et seq. Many of the court decisions discussed in this section involved applications or patents subject to pre-AIA 35 U.S.C. 102. These court decisions may be applicable to applications and patents subject to AIA 35 U.S.C. 102 but the relevant time is before the effective filing date of the claimed invention and not at the time of the invention.]


In order for a reference to be proper for use in an obviousness rejection under 35 U.S.C. 103, the reference must be analogous art to the claimed invention. In re Bigio, 381 F.3d 1320, 1325, 72 USPQ2d 1209, 1212 (Fed. Cir. 2004). A reference is analogous art to the claimed invention if: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); or (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention). Note that "same field of endeavor" and "reasonably pertinent" are two separate tests for establishing analogous art; it is not necessary for a reference to fulfill both tests in order to qualify as analogous art. See Bigio, 381 F.3d at 1325, 72 USPQ2d at 1212. The examiner must determine whether a reference is analogous art when analyzing the obviousness of the subject matter under examination. If a reference is not analogous art to the claimed invention, it may not be used in an obviousness rejection under 35 U.S.C. 103. However, there is no analogous art requirement for a reference being applied in an anticipation rejection under 35 U.S.C. 102. In re Schreiber, 128 F.3d 1473, 1478, 44 USPQ2d 1429, 1432 (Fed. Cir. 1997).

When determining whether the "relevant field of endeavor" test is met, the examiner should consider "explanations of the invention’s subject matter in the patent application, including the embodiments, function, and structure of the claimed invention." Airbus S.A.S. v. Firepass Corp., 941 F.3d 1374, 1380, 2019 USPQ2d 430083 (Fed. Cir. 2019) (quoting Bigio, 381 F.3d at 1325, 72 USPQ2d at 1212). When determining whether a prior art reference meets the "same field of endeavor" test for the analogous art, the primary focus is on what the reference discloses. Airbus, 41 F.3d at 1380. The examiner must consider the disclosure of each reference "in view of the ‘the reality of the circumstances.’" Airbus, 41 F.3d at 1380 (quoting Bigio, 381 F.3d at 1326, 72 USPQ2d at 1212). These circumstances are to be weighed "from the vantage point of the common sense likely to be exerted by one of ordinary skill in the art in assessing the scope of the endeavor." Airbus, 41 F.3d at 1380. See also Donner Technology, LLC v. Pro Stage Gear, LLC, 979 F.3d 1353, 2020 USPQ2d 11335 (Fed. Cir. 2020).

As for the "reasonably pertinent" test, the examiner should consider the problem faced by the inventor, as reflected - either explicitly or implicitly - in the specification. In order for a reference to be "reasonably pertinent" to the problem, it must "logically [] have commended itself to an inventor's attention in considering his problem." In re ICON Health and Fitness, Inc., 496 F.3d 1374, 1379-80 (Fed. Cir. 2007) (quoting In re Clay, 966 F.2d 656,658, 23 USPQ2d 1058, 1061 (Fed. Cir. 1992)). See also In re Klein, 647 F.3d 1343, 1348, 98 USPQ2d 1991, 1993 (Fed. Cir. 2011) An inventor is not expected to have been aware of all prior art outside of the field of endeavor. Airbus, 41 F.3d at 1380-82. A reference outside of the field of endeavor is reasonably pertinent if a person of ordinary skill would have consulted it and applied its teachings when faced with the problem that the inventor was trying to solve. Airbus, 41 F.3d at 1380-82. In order to support a determination that a reference is reasonably pertinent, it may be appropriate to include a statement of the examiner's understanding of the problem. The question of whether a reference is reasonably pertinent often turns on how the problem to be solved is perceived. If the problem to be solved is viewed in a narrow or constrained way, and such a view is not consistent with the specification, the scope of available prior art may be inappropriately limited. It may be necessary for the examiner to explain why an inventor seeking to solve the identified problem would have looked to the reference in an attempt to find a solution to the problem, i.e., factual reasons why the prior art is pertinent to the identified problem. See Donner Tech., LLC v. Pro Stage Gear, LLC, 979 F.3d 1353, 1359, 2020 USPQ2d 11335 (Fed. Cir. 2020) ("Thus, when addressing whether a reference is analogous art with respect to the claimed invention under a reasonable-pertinence theory, the problems to which both relate must be identified and compared.").

The Supreme Court’s decision in KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007), did not change the test for analogous art as stated in Bigio. Under Bigio, a reference need not be from the same field of endeavor as the claimed invention in order to be analogous art. Bigio, 381 F.3d at 1325, 72 USPQ2d at 1212. This is consistent with the Supreme Court's instruction in KSR that "[w]hen a work is available in one field of endeavor, design incentives and other market forces can prompt variations of it, either in the same field or a different one." KSR, 550 U.S. at 417, 82 USPQ2d at 1396.

Any argument by the applicant that the examiner has misconstrued the problem to be solved, and as a result has improperly relied on nonanalogous art, should be fully considered in light of the specification. In evaluating the applicant's argument, the examiner should look to the teachings of the specification and the inferences that would reasonably have been drawn from the specification by a person of ordinary skill in the art as a guide to understanding the problem to be solved. A prior art reference not in the same field of endeavor as the claimed invention must be reasonably pertinent to the problem to be solved in order to qualify as analogous art and be applied in an obviousness rejection.


While Patent Office classification of references and the cross-references in the official search notes of the class definitions are some evidence of "nonanalogy" or "analogy" respectively, the court has found "the similarities and differences in structure and function of the inventions to carry far greater weight." In re Ellis, 476 F.2d 1370, 1372, 177 USPQ 526, 527 (CCPA 1973) (The structural similarities and functional overlap between the structural gratings shown by one reference and the shoe scrapers of the type shown by another reference were readily apparent, and therefore the arts to which the reference patents belonged were reasonably pertinent to the art with which appellant’s invention dealt (pedestrian floor gratings).).


Examples of analogous art in the chemical arts include: Ex parte Bland, 3 USPQ2d 1103 (Bd. Pat App. & Inter. 1986) (Claims were drawn to a particulate composition useful as a preservative for an animal foodstuff (or a method of inhibiting fungus growth in an animal foodstuff therewith) comprising verxite having absorbed thereon propionic acid. All references were concerned with absorbing biologically active materials on carriers, and therefore the teachings in each of the various references would have been pertinent to the problems in the other references and the invention at hand.); Stratoflex, Inc. v. Aeroquip Corp., 713 F.2d 1530, 218 USPQ 871 (Fed. Cir. 1983) (Problem confronting inventor was preventing electrostatic buildup in PTFE tubing caused by hydrocarbon fuel flow while precluding leakage of fuel. Two prior art references relied upon were in the rubber hose art, both referencing the problem of electrostatic buildup caused by fuel flow. The court found that because PTFE and rubber are used by the same hose manufacturers and experience the same and similar problems, a solution found for a problem experienced with either PTFE or rubber hosing would be looked to when facing a problem with the other.); In re Mlot-Fijalkowski, 676 F.2d 666, 213 USPQ 713 (CCPA 1982) (Problem faced by inventor was enhancement and immobilization of dye penetrant indications. References which taught the use of dyes and finely divided developer materials to produce colored images preferably in, but not limited to, the duplicating paper art were properly relied upon because the court found that inventor's problem was one of dye chemistry, and a search for its solution would include the dye arts in general.).


Examples of analogous art in the mechanical arts include: Stevenson v. Int'l Trade Comm., 612 F.2d 546, 550, 204 USPQ 276, 280 (CCPA 1979) ("In a simple mechanical invention a broad spectrum of prior art must be explored and it is reasonable to permit inquiry into other areas where one of ordinary skill in the art would be aware that similar problems exist."). See also In re Bigio, 381 F.3d 1320, 1325-26, 72 USPQ2d 1209, 1211-12 (Fed. Cir. 2004). The patent application claimed a "hair brush" having a specific bristle configuration. The Board affirmed the examiner’s rejection of the claims as being obvious in view of prior art patents disclosing toothbrushes. Id. at 1323, 72 USPQ2d at 1210. The appellant disputed that the patent references constituted analogous art. On appeal, the court upheld the Board’s interpretation of the claim term "hair brush" to encompass any brush that may be used for any bodily hair, including facial hair. Id. at 1323-24, 72 USPQ2d at 1211. With this claim interpretation, the court applied the "field of endeavor test" for analogous art and determined that the references were within the field of the inventor’s endeavor and hence were analogous art because toothbrushes are structurally similar to small brushes for hair, and a toothbrush could be used to brush facial hair. Id. at 1326, 72 USPQ2d at 1212.

Also see In re Deminski, 796 F.2d 436, 230 USPQ 313 (Fed. Cir. 1986) (Appellent's claims related to double-acting high pressure gas transmission line compressors in which the valves could be removed easily for replacement. The Board relied upon references which taught either a double-acting piston pump or a double-acting piston compressor. The court agreed that since the cited pumps and compressors have essentially the same function and structure, the field of endeavor includes both types of double-action piston devices for moving fluids.); Pentec, Inc. v. Graphic Controls Corp., 776 F.2d 309, 227 USPQ 766 (Fed. Cir. 1985) (Claims at issue were directed to an instrument marker pen body, the improvement comprising a pen arm holding means having an integrally molded hinged member for folding over against the pen body. Although the patent owners argued the hinge and fastener art was nonanalogous, the court held that the problem confronting the inventor was the need for a simple holding means to enable frequent, secure attachment and easy removal of a marker pen to and from a pen arm, and one skilled in the pen art trying to solve that problem would have looked to the fastener and hinge art.); and Ex parte Goodyear Tire & Rubber Co., 230 USPQ 357 (Bd. Pat. App. & Inter. 1985) (A reference in the clutch art was held reasonably pertinent to the friction problem faced by the inventor, whose claims were directed to a braking material, because brakes and clutches utilize interfacing materials to accomplish their respective purposes.).


See, for example, Medtronic, Inc. v. Cardiac Pacemakers, 721 F.2d 1563, 220 USPQ 97 (Fed. Cir. 1983) (Patent claims were drawn to a cardiac pacemaker which comprised, among other components, a runaway inhibitor means for preventing a pacemaker malfunction from causing pulses to be applied at too high a frequency rate. Two references disclosed circuits used in high power, high frequency devices which inhibited the runaway of pulses from a pulse source. The court held that one of ordinary skill in the pacemaker designer art faced with a rate-limiting problem would look to the solutions of others faced with rate limiting problems, and therefore the references were in an analogous art.).


See MPEP § 1504.03 for a discussion of the relevant case law setting forth the general requirements for analogous art in design applications.

For examples of analogy in the design arts, see In re Rosen, 673 F.2d 388, 213 USPQ 347 (CCPA 1982) (The design at issue was a coffee table of contemporary styling. The court held designs of contemporary furniture other than coffee tables, such as the desk and circular glass table top designs of the references relied upon, would reasonably fall within the scope of the knowledge of the designer of ordinary skill.); Ex parte Pappas, 23 USPQ2d 1636 (Bd. Pat. App. & Inter. 1992) (At issue was an ornamental design for a feed bunk with an inclined corner configuration. Examiner relied upon references to a bunk lacking the inclined corners claimed by appellant and the Architectural Precast Concrete Drafting Handbook. The Board found the Architectural Precast Concrete Drafting Handbook was analogous art, noting that a bunk may be a wood or concrete trough, and that both references relied upon "disclose structures in which at least one upstanding leg is generally perpendicular to a base portion to define a corner configuration between the leg and base portion."); In re Butera, 1 F.3d 1252, 28 USPQ2d 1399, 1400 (Fed. Cir. 1993) (unpublished - not citable as precedent) (The claimed invention, a spherical design for a combined insect repellent and air freshener, was rejected by the Board as obvious over a single reference to a design for a metal ball anode. The court reversed, holding the reference design to be nonanalogous art. "A prior design is of the type claimed if it has the same general use as that claimed in the design patent application.... One designing a combined insect repellent and air freshener would therefore not have reason to know of or look to a design for a metal ball anode.").