Hold up a Phillips-head screwdriver and a battery-powered drill. Each existed before someone put them together; the cordless screwdriver is "nothing but" a known bit fastened to a known motor. And yet patents on power tools issue every year. Why? Because patent law refuses to play the parlor game in which every invention, taken apart and laid on the table after the fact, looks like an obvious heap of pre-existing parts. The whole discipline of obviousness analysis is an elaborate machine built for one purpose: to figure out whether an invention was a genuine advance or merely the next predictable step — and to do so without cheating by peeking at the answer the inventor already supplied.

Of all the hurdles between an inventor and an enforceable patent, obviousness is the highest, the most frequently encountered, and the most slippery. Anticipation under 35 U.S.C. § 102 is comparatively clean: either a single prior-art reference describes every element of the claim, arranged as claimed, or it does not. Obviousness under 35 U.S.C. § 103 is different in kind. It asks a counterfactual, judgment-laden question — would the claimed invention as a whole have been obvious to a person of ordinary skill in the art before the effective filing date? — and it lets the examiner or an accused infringer build that case from several references stitched together, from a single reference modified in light of ordinary skill, or even from "common sense." Because the inquiry is so open-textured, it is also where the most prosecution responses are won and lost, and where the most issued patents are ultimately struck down.

This article is a practical, end-to-end guide to § 103, written so that a patent practitioner can lift strategy from it, a judge or generalist litigator can follow the doctrine, and an inventor or business owner with no legal training can understand what is happening to their application and why. We start with the statute and the two Supreme Court decisions that frame everything — Graham v. John Deere Co., 383 U.S. 1 (1966), and KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007). We then dissect what the government or a challenger must prove to establish a prima facie case (a Latin phrase meaning "on first appearance" — a showing strong enough to shift the burden if left unrebutted), and the full menu of substantive responses: attacking the motivation to combine, negating the reasonable expectation of success, teaching away, non-analogous art, change in the principle of operation, and the objective indicia of nonobviousness. Finally, we cover the mechanics — amendments, declarations, examiner interviews, the duty of candor — and the very different rules of engagement at the U.S. Patent and Trademark Office (USPTO), the Patent Trial and Appeal Board (PTAB), and the district court.

If you are responding to an Office action right now, you will also want our companion piece, Responding to Patent Office Actions — Strategies for Overcoming Rejections, which covers the procedural scaffolding — non-final versus final, after-final practice, and appeals — into which the substantive arguments below must fit. And if the vocabulary here is unfamiliar, Patent Basics — A Plain-English Guide and Utility Patent Basics lay the groundwork that this article assumes.

What § 103 Actually Says, and Why It Exists

Section 103 of the Patent Act provides, in its post-America Invents Act (AIA) form, that a patent may not be obtained "if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains." The pre-AIA version, which still governs applications and patents with effective filing dates before March 16, 2013, phrased the temporal reference point as "at the time the invention was made" rather than "before the effective filing date," but the analytical structure is identical. Knowing which regime applies matters at the threshold, because it changes what qualifies as prior art in the first place — a point we return to below.

The policy behind § 103 is easy to state and hard to apply. The patent bargain trades a limited monopoly for a genuine contribution to the public storehouse of knowledge. Anticipation polices the requirement that the invention be new. Obviousness polices the requirement that it be a real advance — that it not be merely the routine, predictable next step that any competent worker in the field would have taken. As the Supreme Court put it long before Graham, "the device, though new and useful, must reveal the flash of creative genius, not merely the skill of the calling." Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84, 91 (1941). Congress repudiated that "flash of genius" language as a workable test when it enacted § 103 in the 1952 Patent Act — the statute pointedly adds that "[p]atentability shall not be negated by the manner in which the invention was made" — but the underlying intuition survives: a patent should not lock up what ordinary skill, applied to known materials, would have produced as a matter of course.

The difficulty is that almost every invention, viewed in retrospect, looks like an obvious combination of things that already existed. The cordless screwdriver again. Hindsight is the enemy of fair obviousness analysis, and most of the doctrine we are about to discuss is, at bottom, machinery designed to keep the analysis honest by anchoring it to the knowledge and motivations that actually existed before the invention was made.

The Graham Framework: The Four Factual Inquiries

In Graham v. John Deere Co., the Supreme Court read § 103 — then only recently enacted — and supplied the analytical structure that has governed ever since. Obviousness is ultimately a question of law, the Court held, but it rests on several underlying questions of fact. Those Graham factors are:

  1. The scope and content of the prior art — what was publicly known and available, whether patents, printed publications, products, or other prior art, as of the relevant date.
  2. The differences between the prior art and the claims at issue — what, exactly, the claim adds to or changes from what was already known.
  3. The level of ordinary skill in the pertinent art — who the hypothetical "person of ordinary skill in the art" (often abbreviated POSITA) is, and what education, experience, and creativity that person possesses.
  4. Secondary considerations — objective, real-world evidence such as commercial success, long-felt but unsolved need, and the failure of others, which can shed light on whether the invention was truly obvious.

Graham, 383 U.S. at 17–18. The first three inquiries are often called the "primary" Graham factors and the fourth the "secondary considerations" or, in more modern usage, the "objective indicia of nonobviousness." It is a mistake — though a common one — to treat the fourth factor as an afterthought. The Federal Circuit has repeatedly held that secondary considerations must be considered as part of the obviousness determination, not as a tiebreaker after a preliminary conclusion has already been reached. See In re Cyclobenzaprine Hydrochloride Extended-Release Capsule Patent Litigation, 676 F.3d 1063, 1075–80 (Fed. Cir. 2012) (the fact finder must weigh objective evidence before reaching the ultimate obviousness conclusion). A fact finder who announces a conclusion on the primary factors and only then "checks" it against the objective evidence has committed legal error.

Meet the Person of Ordinary Skill

The "person of ordinary skill in the art" deserves a word for non-specialists, because almost everything else in § 103 is measured from this character's vantage point. The POSITA is a legal construct, much like the "reasonable person" of tort law — a useful fiction who is presumed to know all of the relevant prior art and to possess the ordinary creativity and problem-solving ability of a worker in the field. Not the genius of the inventor; not a robot mechanically reading references either. Courts gauge the POSITA's level of skill by weighing the educational level of workers in the field, the types of problems encountered, prior-art solutions to those problems, the rapidity with which innovations are made, and the sophistication of the technology. Daiichi Sankyo Co. v. Apotex, Inc., 501 F.3d 1254, 1256 (Fed. Cir. 2007).

Defining the POSITA's skill level is not a sterile preliminary; it frequently decides the case. The higher the skill level, the more a given combination looks obvious, because a more sophisticated worker is more likely to bridge the gap between references. The lower the skill level, the more an invention appears inventive. This is why a challenger's counsel routinely argues for a higher level of skill — more advanced degrees, more years in the industry, more hands-on experience with the specific application — while the patent owner argues for a more modest one. The dispute over who the POSITA is, in other words, is often a proxy for the dispute over whether the invention was obvious at all.

KSR v. Teleflex and the Death of the Rigid TSM Test

For roughly two decades before 2007, the Federal Circuit had developed a doctrine known as the teaching-suggestion-motivation test, or TSM. Under TSM as it came to be applied, an examiner or challenger generally could not combine two prior-art references to render a claim obvious unless there was some explicit teaching, suggestion, or motivation — found in the references themselves, the nature of the problem, or the knowledge of the POSITA — to make that particular combination. The test had a worthy purpose: it was a hindsight prophylactic, designed to prevent an examiner armed with the applicant's own disclosure from gathering scattered prior-art pieces and announcing the combination obvious. The problem, in the Supreme Court's view, was that the Federal Circuit had hardened TSM into a rigid, mandatory formula and demanded a degree of explicitness that the real world of innovation rarely supplies.

KSR International Co. v. Teleflex Inc. changed that. The case involved an adjustable automobile gas pedal combined with an electronic position sensor — two known things combined to achieve a predictable result. The Supreme Court reversed the Federal Circuit's reversal of summary judgment of obviousness and used the occasion to recalibrate the entire doctrine. Its central holdings reverberate through every § 103 dispute today:

  • The TSM test is not the exclusive test. A flexible, expansive analysis is required. The motivation to combine "need not be found explicitly in the prior art"; courts and examiners may take account of "the inferences and creative steps that a person of ordinary skill in the art would employ." KSR, 550 U.S. at 418.
  • The POSITA is a person of ordinary creativity, not an automaton. Id. at 421.
  • Predictable variations are obvious. "When 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. If a person of ordinary skill can implement a predictable variation, § 103 likely bars its patentability." Id. at 417.
  • The "obvious to try" rationale is rehabilitated. Where there is "a design need or market pressure to solve a problem and there are a finite number of identified, predictable solutions," pursuing the known options may be obvious to try, and if it yields the anticipated success, it is likely obvious. Id. at 421.
  • Hindsight remains forbidden, but the warning is recalibrated. A patent "composed of several elements is not proved obvious merely by demonstrating that each of its elements was, independently, known in the prior art," id. at 418, and "a factfinder should be aware, of course, of the distortion caused by hindsight bias and must be cautious of arguments reliant upon ex post reasoning." Id. at 421.

The practical upshot of KSR is double-edged. It made obviousness rejections and invalidity defenses easier to assert: examiners and challengers can now invoke common sense, market forces, and predictable variations without locating a smoking-gun teaching in the references. The obviousness inquiry may now take into account "the logic, judgment, and common sense" available to the POSITA, Perfect Web Technologies, Inc. v. InfoUSA, Inc., 587 F.3d 1324, 1329 (Fed. Cir. 2009), including matters within a skilled artisan's general knowledge if supported by the record, Koninklijke Philips N.V. v. Google LLC, 948 F.3d 1330, 1337–38 (Fed. Cir. 2020).

But KSR did not dispense with the requirement of a reasoned explanation. The post-KSR Federal Circuit has been emphatic: there must still be "articulated reasoning with some rational underpinning to support the legal conclusion of obviousness." In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006), quoted approvingly in KSR, 550 U.S. at 418. Conclusory invocations of "common sense" do not survive appellate scrutiny. See In re Nuvasive, Inc., 842 F.3d 1376, 1383–85 (Fed. Cir. 2016) (vacating a PTAB obviousness finding for failure to articulate why a POSITA would have combined the references with a reasonable expectation of success); Arendi S.A.R.L. v. Apple Inc., 832 F.3d 1355, 1361–62 (Fed. Cir. 2016) (common sense cannot serve as a wholesale substitute for reasoned analysis and evidentiary support, especially to supply a missing claim limitation). The lesson is that the death of rigid TSM did not abolish the motivation requirement; it loosened the source from which motivation may be drawn while keeping the demand for explanation. Indeed, a defensible version of TSM survives as one of the USPTO's recognized rationales — it is simply no longer the only path.

The Anatomy of a Prima Facie Case of Obviousness

In prosecution, the examiner bears the initial burden of establishing a prima facie case of obviousness. See 35 U.S.C. § 132; 37 C.F.R. § 1.104; In re Dillon, 919 F.2d 688, 696, 701 (Fed. Cir. 1990); Manual of Patent Examining Procedure (MPEP) §§ 2142, 2143. Only once the examiner has carried that burden does the burden of going forward shift to the applicant to rebut it. MPEP § 2145. Understanding the elements of the examiner's burden is the foundation of every effective response, because the most efficient way to overcome a rejection is frequently to show that the prima facie case was never properly made in the first place — a point that costs nothing in claim scope.

A proper prima facie obviousness rejection has three components, drawn from Graham and refined by KSR.

First, the examiner must identify all the differences between the claimed invention and the prior art. This requires a correct claim construction (the legal interpretation of the claim's words) under the broadest-reasonable-interpretation (BRI) standard used in examination, and a faithful mapping of each claim limitation to the references. Under BRI, the examiner gives claim terms their ordinary and customary meaning to a POSITA in light of the specification, without importing limitations from the specification into the claims. Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005); MPEP §§ 2111 to 2111.04. A rejection that ignores a limitation, misreads a claim term, or glosses over a limiting preamble is vulnerable from the start.

Second, the examiner must articulate a reason — a "rationale" — why a POSITA would have combined or modified the references to arrive at the claimed invention. This is the motivation-to-combine requirement, and it is the heart of the prima facie case. KSR, 550 U.S. at 418; MPEP §§ 2143, 2143.01, 2144.

Third, the examiner must establish that the POSITA would have had a reasonable expectation of success in making the combination. This requirement, discussed in detail below, polices against rejections that assume a combination would have worked when the art gave no such assurance. MPEP § 2143.02; In re Kubin, 561 F.3d 1351, 1359–60 (Fed. Cir. 2009).

In practice, the examiner usually builds the case by identifying a primary reference disclosing most of the claim elements, citing one or more secondary references for the missing elements, and then asserting both a motivation to combine and a reasonable expectation of success. See In re Cyclobenzaprine, 676 F.3d at 1068–69.

The Seven KSR Rationales — and Their Hidden Predicates

After KSR, the USPTO published a set of exemplary rationales that examiners may invoke to supply the required reasoning. They live in MPEP § 2143 and are worth knowing by name, because a response often turns on showing that the cited rationale does not actually fit the facts:

  1. Combining prior-art elements according to known methods to yield predictable results.
  2. Simple substitution of one known element for another to obtain predictable results.
  3. Use of a known technique to improve a similar device, method, or product in the same way.
  4. Applying a known technique to a known device, method, or product ready for improvement to yield predictable results.
  5. "Obvious to try" — choosing from a finite number of identified, predictable solutions with a reasonable expectation of success.
  6. Known work in one field of endeavor prompting variations in the same or a different field based on design incentives or market forces, where the variations are predictable to a POSITA.
  7. Some teaching, suggestion, or motivation in the prior art that would have led a POSITA to modify or combine the references — i.e., the surviving, non-exclusive version of TSM.

Here is the part many responses miss: the MPEP itself instructs that each rationale has factual predicates the examiner must establish. The rationale is a label, not a conclusion. For the "obvious to try" rationale, for instance, there must genuinely be a finite number of identified, predictable solutions; an art with infinite parameters, or one in which the outcome is unpredictable, does not support the rationale. In re Kubin, 561 F.3d at 1359 (distinguishing genuine "obvious to try" situations from "throwing metaphorical darts at a board"). For "simple substitution," the substituted element must have been a known equivalent functioning in the same way to yield a predictable result. When a rejection invokes a rationale without establishing its predicates, the response should say so directly and quote the MPEP's own requirements back to the examiner — a move that reframes the dispute from "is this obvious?" (a debate the examiner is comfortable having) to "has the examiner met the agency's own checklist?" (a debate the applicant often wins on the paper).

Attacking the Motivation to Combine

Because motivation to combine is the linchpin of nearly every multi-reference obviousness rejection, it is also the most productive line of attack. The argument is rarely that the individual elements are missing — they usually are present somewhere in the art. It is that the examiner has not shown why a POSITA would have selected and assembled those particular elements in the claimed way, other than by using the applicant's own disclosure as a roadmap. That is the classic signature of impermissible hindsight, and counsel should not hesitate to name it. See Sanofi-Synthelabo v. Apotex, Inc., 550 F.3d 1075, 1088 (Fed. Cir. 2008) (cautioning against using hindsight to read the invention's teachings into the prior art).

Several recurring sub-arguments fall under this heading.

The references are too different to combine. When references come from disparate technical contexts, operate at different scales, or serve materially different purposes, those substantial differences weigh against any motivation to combine. The Federal Circuit has said so directly: pointing out significant differences between the references an accused infringer seeks to combine "may weigh against a motivation to combine." Adidas AG v. Nike, Inc., 963 F.3d 1355, 1359–60 (Fed. Cir. 2020).

The combination is conclusory. A rejection that recites one of the MPEP rationales as a bare conclusion — "it would have been obvious to combine A and B because doing so yields predictable results" — without explaining why the result would have been predictable or what in the art prompts the combination is precisely the unsupported assertion the Federal Circuit keeps rejecting. In re Nuvasive, 842 F.3d at 1383–85; Arendi, 832 F.3d at 1361–62. The response should quote the rejection's own language and expose the gap between recital and reasoning. The same standard binds challengers in litigation: any assertion of "common sense" or expert "wisdom" must be backed by a reasoned analysis in the record, not floated as ipse dixit. Arendi, 832 F.3d at 1366.

The proposed combination would not work or would defeat the references' purpose. This shades into "teaching away" and "change in principle of operation," discussed below, but at the motivation stage the point is narrower: if combining the references would render one of them unsatisfactory for its intended purpose, a POSITA would have had no reason to make the combination. In re Gordon, 733 F.2d 900, 902 (Fed. Cir. 1984) (no obviousness where the proposed modification would render the prior-art device inoperable for its intended purpose).

One caution running the other way. An examiner or challenger need not find an express teaching to combine if a POSITA would have purposefully made the combination based on the information available at the time. Allergan, Inc. v. Apotex Inc., 754 F.3d 952, 963–64 (Fed. Cir. 2014). The point of a motivation attack, then, is not to demand explicit language that KSR abolished, but to show that even the flexible, common-sense inquiry yields no genuine reason — only hindsight.

A Worked Hypothetical: Acme's Filtration Bottle

A short example makes the structure concrete. This is a hypothetical. Suppose Acme Corp. claims a portable water-filtration bottle in which a hollow-fiber membrane cartridge is integrated into the bottle cap so the user drinks through the cap. The examiner cites Reference 1, a countertop water filter using a hollow-fiber membrane, and Reference 2, a sports bottle with a flip-up drinking spout, and asserts that combining them is a "simple substitution" yielding predictable results.

Acme's response challenges the motivation on its own terms. Reference 1's membrane is engineered for gravity-fed, low-pressure countertop use; Reference 2 says nothing about filtration; and neither reference suggests that a membrane sized and configured for countertop pressures could be adapted to the cyclical suction pressures of a drinking bottle while maintaining flow rate and pore integrity. The examiner has identified two known things but has not explained why a POSITA would have combined these elements in this way — nor why doing so would predictably work. That second gap leads directly into the reasonable-expectation-of-success requirement.

Reasonable Expectation of Success

A motivation to combine is necessary but not sufficient. The POSITA must also have had a reasonable expectation of success — a reasonable basis to expect that the combination or modification would actually achieve the claimed result. The two requirements are distinct: one can have every reason in the world to want to combine two references and still lack any reasonable basis to expect that the combination would work. Intelligent Bio-Systems, Inc. v. Illumina Cambridge Ltd., 821 F.3d 1359, 1367–68 (Fed. Cir. 2016) (motivation and reasonable expectation of success are separate inquiries).

The standard is not certainty. "Obviousness does not require absolute predictability of success." In re O'Farrell, 853 F.2d 894, 903–04 (Fed. Cir. 1988). But there must be more than a hope or "a general motivation to make some change." The prior art must provide "some indication" of which parameters are critical and which of the available options is likely to succeed. In re Kubin, 561 F.3d at 1359–60. If the actual result would have been easily predictable, the expectation of success follows readily. Perfect Web, 587 F.3d at 1331.

This is where the predictability of the art becomes one of the most important framing decisions in any obviousness dispute. In predictable arts — most mechanical and electronic technologies, including many computer-implemented inventions — the bar is lower, because predictable results flow more readily from known combinations. In unpredictable arts — chemistry, pharmaceuticals, biotechnology, and much of materials science — the prima facie case demands more: a specific motivation to modify or combine and concrete evidence supporting a reasonable expectation of success, often including experimental data. Orexo AB v. Actavis Elizabeth LLC, 903 F.3d 1265, 1272–73 (Fed. Cir. 2018); Endo Pharmaceuticals Solutions, Inc. v. Custopharm Inc., 894 F.3d 1374, 1380–81 (Fed. Cir. 2018); Eisai Co. v. Dr. Reddy's Laboratories, Ltd., 533 F.3d 1353, 1359 (Fed. Cir. 2008). The USPTO recognizes this asymmetry expressly, maintaining separate examination guidance for predictable and unpredictable technologies precisely because prior art in unpredictable fields is less likely to predict improvements or lead a POSITA to the claimed invention.

A patent owner whose invention lies in an unpredictable field should foreground that unpredictability: emphasize the number of interdependent variables, the documented surprises and failures in the literature, and the absence of any reliable basis from which a POSITA could have predicted that the specific claimed combination would succeed. Where there is "no evidence that a person of ordinary skill in the art would have had a reasonable expectation of success with any one of many available experiments or combinations," the invention is not obvious. In re Cyclobenzaprine, 676 F.3d at 1072–73.

A Note on Inherency

Examiners and challengers sometimes try to shore up a shaky combination by arguing that a missing limitation is inherently present — that it is "the natural result" of combining the cited references. Persion Pharmaceuticals LLC v. Alvogen Malta Operations Ltd., 945 F.3d 1184, 1190–91 (Fed. Cir. 2019). Inherency is applied narrowly in the obviousness context, and it has firm limits worth knowing. Inherency can supply a claim feature that necessarily flows from the combination, but it cannot supply the reason to combine in the first place. See Honeywell International Inc. v. Mexichem Amanco Holding S.A., 865 F.3d 1348, 1354 (Fed. Cir. 2017); PAR Pharmaceutical, Inc. v. TWI Pharmaceuticals, Inc., 773 F.3d 1186, 1194–95 (Fed. Cir. 2014). A property is not inherent simply because it is "possible" or even "probable"; it must be necessarily present. When a rejection leans on inherency to bridge a logical gap in the motivation analysis, that misuse is itself a basis to attack the rejection.

Returning to Acme's bottle: even if the examiner could articulate a motivation to integrate a membrane into a cap, Acme can argue that nothing in the cited art gives a POSITA a reasonable expectation that a hollow-fiber membrane would retain adequate flow rate and bacterial-retention performance under the cyclical negative pressure of human suction rather than steady gravity feed. If Acme has test data showing that off-the-shelf membranes failed under those conditions until its specific fiber-bundle geometry was developed, that data does double duty: it negates the reasonable expectation of success and supports an unexpected-results argument under the objective indicia.

Teaching Away

A reference teaches away from the claimed invention when "a person of ordinary skill, upon reading the reference, would be discouraged from following the path set out in the reference, or would be led in a direction divergent from the path that was taken by the applicant." In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994); see also Tec Air, Inc. v. Denso Manufacturing Michigan Inc., 192 F.3d 1353, 1360 (Fed. Cir. 1999). A reference that criticizes, discredits, or otherwise discourages the claimed approach undercuts the obviousness case, because a POSITA reading it would be steered away from the very combination the examiner says was obvious. Ricoh Co. v. Quanta Computer Inc., 550 F.3d 1325, 1332 (Fed. Cir. 2008); see also Bradium Technologies LLC v. Iancu, 923 F.3d 1032, 1047 (Fed. Cir. 2019).

Teaching away is one of the most rhetorically powerful arguments available — and one of the most frequently overstated, so precision matters. A few principles govern.

  • Mere disclosure of an alternative is not teaching away. That a reference discloses a different, or even a preferred, embodiment does not mean it teaches away from the claimed one. "A reference does not teach away ... if it merely expresses a general preference for an alternative invention." Meiresonne v. Google, Inc., 849 F.3d 1379, 1382 (Fed. Cir. 2017); see also In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004).
  • There must be actual discouragement or criticism. The strongest teaching-away showings rest on explicit statements that the claimed approach would not work, would be inferior, or would produce undesirable results. Disclosed drawbacks of the claimed path, an emphasis on operating principles incompatible with the claim, or a description of technical incompatibilities can all supply the requisite discouragement.
  • Teaching away can negate motivation or expectation of success. Functionally, a teaching-away argument often works by undermining the motivation to combine (a POSITA discouraged from the path would not pursue it) or the reasonable expectation of success (the art predicts failure, not success).

In prosecution, the most effective teaching-away response quotes the discouraging language verbatim, explains in plain terms what a POSITA reading that passage would conclude, and ties it to the specific modification the examiner proposes. Generalized assertions that "the art teaches away," untethered to a pinpoint citation, rarely persuade an examiner and almost never persuade the Board.

Non-Analogous Art

Prior art may be used in an obviousness rejection only if it is analogous to the claimed invention. A reference is analogous if it satisfies either of two tests: (1) it is from the same field of endeavor as the claimed invention, regardless of the problem addressed; or (2) even if outside that field, it is reasonably pertinent to the particular problem with which the inventor was concerned. In re Clay, 966 F.2d 656, 658–59 (Fed. Cir. 1992); In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004).

The analogous-art requirement is itself a hindsight safeguard. Without it, a challenger could roam across every field of human endeavor to find a stray disclosure of a single claim element, no matter how remote from the inventor's world. The "reasonably pertinent" prong asks whether the reference "logically would have commended itself to an inventor's attention in considering his problem." In re Clay, 966 F.2d at 659. A reference from a distant field that addresses a fundamentally different problem fails both prongs.

It must be candidly noted that KSR loosened the practical force of this doctrine. The Court stressed that "familiar items may have obvious uses beyond their primary purposes, and in many cases a person of ordinary skill will be able to fit the teachings of multiple patents together like pieces of a puzzle," and that design incentives in one field can prompt variations in another. KSR, 550 U.S. at 402, 420. The Federal Circuit nonetheless continues to enforce the analogous-art limits, and the argument retains real force where the cited reference is genuinely remote. See In re Klein, 647 F.3d 1343 (Fed. Cir. 2011) (reversing where the cited references were not reasonably pertinent to the inventor's problem of a nectar-mixing device). To make the argument well, define the field of endeavor and the inventor's specific problem with care, then demonstrate why the cited reference addresses neither. A precise framing of "the problem the inventor faced" is doing most of the work here — frame it narrowly and a far-flung reference falls outside it.

Change in Principle of Operation and Loss of Beneficial Properties

Two closely related arguments target modifications that would fundamentally alter, rather than merely improve, a prior-art device.

The change in principle of operation argument derives from In re Ratti, 270 F.2d 810, 813 (CCPA 1959), which held that a combination requiring "a substantial reconstruction and redesign of the elements shown ... as well as a change in the basic principles under which the [prior art] construction was designed to operate" is improper. The logic is that a POSITA would not be motivated to so transform a reference, and that doing so amounts to redesigning the prior art using the patent as a blueprint. The argument is strongest when the references operate on contradictory principles, when combining them would require fundamental rather than routine redesign, or when the modification would defeat the reference's core purpose. See also In re Gordon, 733 F.2d at 902.

The loss of beneficial properties argument is a cousin: if the proposed modification would eliminate a benefit the prior art was specifically designed to provide, a POSITA would have been discouraged from making it. In re Wesslau, 353 F.2d 238, 241 (CCPA 1965) (improper to combine references where doing so would produce a device lacking the advantages of the prior-art devices). If the proposed combination would compromise core functionality, eliminate an advantageous feature, introduce a new failure mode, or degrade reliability or performance, the response should identify the lost benefit specifically and explain why its loss would have deterred the POSITA.

These arguments are often best deployed alongside teaching-away and motivation-to-combine attacks, because they all converge on the same point: a POSITA standing in the prior art, without the benefit of the applicant's disclosure, would not have made the modification the examiner posits.

Lack of an Enabling Disclosure for the Proposed Combination

A distinct but underused argument attacks the enablement of the combination itself. For an obviousness rejection to be proper, the prior art relied upon must enable a POSITA to make and use the claimed invention without undue experimentation; a reference cannot render a claim obvious if it does not enable the very subject matter the examiner builds the combination from. In re Hoeksema, 399 F.2d 269, 274 (CCPA 1968). The point bites where the cited art gestures at a result but supplies no workable path to it — where there is no guidance on the critical modification, no instruction on how to maintain core functionality once the references are combined, no information on material compatibility, and no discussion of how a POSITA would have overcome the technical obstacles the combination creates. When the only "teaching" of the combination is the applicant's own specification, the references are non-enabling for that purpose, and an obviousness rejection cannot stand on them. This argument pairs naturally with the reasonable-expectation-of-success attack: art that does not enable the combination rarely supplies any basis to expect it would have worked.

The Objective Indicia of Nonobviousness (Secondary Considerations)

We now arrive at the fourth Graham factor — which the Federal Circuit has called, in case after case, "often the most probative and cogent evidence of nonobviousness in the record." Pro-Mold & Tool Co. v. Great Lakes Plastics, Inc., 75 F.3d 1568, 1573 (Fed. Cir. 1996); see also Leo Pharmaceutical Products, Ltd. v. Rea, 726 F.3d 1346, 1358 (Fed. Cir. 2013). These indicia carry such weight precisely because they are objective: real-world facts about how the invention fared in the marketplace and in the hands of skilled workers. As such they "counterbalance any inadvertent use of hindsight," "help inoculate the obviousness analysis against hindsight," and "place a scientific advance in the proper temporal and technical perspective." Mintz v. Dietz & Watson, Inc., 679 F.3d 1372, 1378 (Fed. Cir. 2012). Where the primary Graham factors are a debate about what a hypothetical person would have thought, the secondary considerations are a record of what real people actually did.

The principal objective indicia are commercial success, long-felt but unsolved need, failure of others, skepticism, copying, industry praise, licensing, and unexpected results. See Power Integrations, Inc. v. Fairchild Semiconductor International, Inc., 711 F.3d 1348, 1368 (Fed. Cir. 2013). Two threshold points apply across all of them. First, the objective evidence must be weighed as part of the obviousness determination, not after a tentative conclusion has been reached. In re Cyclobenzaprine, 676 F.3d at 1075–80. Second — and this is the requirement that defeats more objective-indicia showings than any other — there must be a nexus between the evidence and the claimed invention.

The Nexus Requirement

Nexus is the legally and factually required connection between the objective evidence and the merits of the claimed invention. Commercial success that flows from the inventor's marketing budget, from unclaimed features, or from sheer market power has no probative value, because it says nothing about whether the claimed technical contribution was obvious.

The Federal Circuit applies a structured nexus analysis. Where the patented invention is coextensive with the product or process that achieved the success — that is, the product essentially is the claimed invention, with no significant unclaimed features — nexus is presumed. Fox Factory, Inc. v. SRAM, LLC, 944 F.3d 1366, 1373–74 (Fed. Cir. 2019); PPC Broadband, Inc. v. Corning Optical Communications RF, LLC, 815 F.3d 747, 755 (Fed. Cir. 2016). But where the product contains significant features not covered by the claim, it is not coextensive, the presumption does not apply, and the patentee must affirmatively demonstrate that the objective evidence is attributable to the claimed features rather than to those unclaimed features or to extraneous factors. Fox Factory, 944 F.3d at 1373–74; Demaco Corp. v. F. Von Langsdorff Licensing Ltd., 851 F.2d 1387, 1392 (Fed. Cir. 1988). Even without the presumption, the patentee may establish nexus directly by showing the success is the "direct result of the unique characteristics of the claimed invention." Fox Factory, 944 F.3d at 1373.

A subtle but important refinement: nexus need not always be tied to a single new feature. The patentee may demonstrate nexus to the claimed combination as a whole, even if the individual elements were known. Henny Penny Corp. v. Frymaster LLC, 938 F.3d 1324, 1333–34 (Fed. Cir. 2019); WBIP, LLC v. Kohler Co., 829 F.3d 1317, 1330 (Fed. Cir. 2016). This matters because the entire premise of a combination invention is that the combination is new even though the parts are old; nexus law accommodates that reality.

Commercial Success

Commercial success of a product embodying the claimed invention supports nonobviousness on the theory that, if the invention had really been obvious, competitors operating in the same market would have brought it to market sooner. Merck & Co. v. Teva Pharmaceuticals USA, Inc., 395 F.3d 1364, 1376 (Fed. Cir. 2005). The claimed invention need not be the sole cause of the success — it is enough that there is a connection between the commercial success and the claimed features. Continental Can Co. USA, Inc. v. Monsanto Co., 948 F.2d 1264, 1273 (Fed. Cir. 1991). But raw sales figures alone are usually insufficient: high volume says little without market-share context and a demonstrated nexus to the claimed features. In re Huang, 100 F.3d 135, 140 (Fed. Cir. 1996). The patentee must also rebut alternative explanations — heavy advertising, brand strength, an installed-base lock-in, bundling, competitive pricing, or market power — that could account for the success independent of the invention's merits. Id. The challenger, predictably, will marshal exactly those alternatives.

Long-Felt but Unsolved Need and Failure of Others

Evidence that the industry recognized a problem for a long time, demanded a solution, and yet failed to find one until the claimed invention appeared supports nonobviousness. The inference is straightforward: if the solution had been obvious, skilled workers — demonstrably motivated to solve the problem — would have found it sooner. The Supreme Court recognized the force of this evidence well over a century ago, treating an invention's swift adoption to fill a long-standing want as proof that it was no mere obvious step. See Smith v. Goodyear Dental Vulcanite Co., 93 U.S. 486, 495–96 (1876). To carry the argument, counsel must show recognition of the problem for a considerable time, that the claimed invention solved it, and that the solution did not merely ride on an unrelated advance in the field. Perfect Web, 587 F.3d at 1332; In re Cyclobenzaprine, 676 F.3d at 1082–83.

The closely related failure of others indicium points to documented, unsuccessful attempts by others to solve the same problem; such failures tend to negate any reasonable expectation of success and therefore obviousness. In re Cyclobenzaprine, 676 F.3d at 1081. One important caveat: failure of others is discounted as an indicator of nonobviousness where a blocking patent deterred others from even attempting the work for legal rather than technical reasons. Acorda Therapeutics, Inc. v. Roxane Laboratories, Inc., 903 F.3d 1310, 1337–39 (Fed. Cir. 2018). A symmetrical caution cuts the other way for patent owners: evidence that several people arrived at the same solution within the same general time frame (near-simultaneous invention) can refute long-felt need and even serve as an indicator of obviousness. Ecolochem, Inc. v. Southern California Edison Co., 227 F.3d 1361, 1379 (Fed. Cir. 2000).

Skepticism, Copying, Industry Praise, and Licensing

Skepticism or disbelief in the relevant community before the invention proved itself supports nonobviousness — for example, evidence that skilled workers did not believe the invention would accomplish its purpose until they saw it work, or that the inventors had trouble publishing their results or were turned away by conference organizers. Kinetic Concepts, Inc. v. Smith & Nephew, Inc., 688 F.3d 1342, 1367 (Fed. Cir. 2012). A mere request for confirmatory data, however, is not skepticism; it does not show that a POSITA would have been surprised the invention worked. Bayer Healthcare Pharmaceuticals, Inc. v. Watson Pharmaceuticals, Inc., 713 F.3d 1369, 1377 (Fed. Cir. 2013).

Evidence that a competitor copied the claimed invention — rather than designing around it or adopting a non-infringing alternative — supports nonobviousness, on the premise that skilled competitors would generally prefer to obtain the same benefits without copying if obvious alternatives existed. Wm. Wrigley Jr. Co. v. Cadbury Adams USA LLC, 683 F.3d 1356, 1364 (Fed. Cir. 2012). Copying requires a nexus too; mere evidence that a competitor sells a similar product is not enough, and some courts discount copying as possibly reflecting indifference to patent rights rather than recognition of inventive merit. Ecolochem, 227 F.3d at 1380. (In Hatch-Waxman litigation, copying is generally not probative, because a generic applicant must show bioequivalence to obtain FDA approval. Bayer, 713 F.3d at 1377.)

Industry praise — recognition by experts, awards, and favorable trade-press coverage — supports nonobviousness when tied to the claimed aspects of the invention. Apple Inc. v. Samsung Electronics Co., 839 F.3d 1034, 1052–53 (Fed. Cir. 2016) (en banc). Note that articles authored by the named inventors, or merely citing their results, are generally not viewed as objective and carry little weight. Bayer, 713 F.3d at 1377. Finally, licensing by others can corroborate nonobviousness, but only if it flows from the technical merits rather than a desire to avoid litigation costs.

Unexpected Results

When a combination of known elements produces results greater than or different from what a POSITA would have predicted, that unexpectedness is strong evidence of nonobviousness, because it shows the POSITA would not have had a reasonable expectation of success. Crocs, Inc. v. International Trade Commission, 598 F.3d 1294, 1309 (Fed. Cir. 2010); Procter & Gamble Co. v. Teva Pharmaceuticals USA, Inc., 566 F.3d 989, 997 (Fed. Cir. 2009). Unexpected results are especially potent in chemical and pharmaceutical cases, where they are typically established through side-by-side comparative testing against the closest prior art. To carry weight, the results must be (1) genuinely unexpected to the POSITA at the relevant time, (2) commensurate in scope with the claims, and (3) compared against the closest prior art rather than a strawman. A difference in degree may suffice if it amounts to a difference of kind in practical effect or is otherwise surprising. This is the one objective indicium that bears directly on the prima facie case rather than merely rebutting it — which is why it is so valuable.

Translating Doctrine Into a Prosecution Response

We now turn from doctrine to practice. When an Office action arrives rejecting claims under § 103, an organized, layered response is far more effective than a one-note argument. The following sequence reflects how experienced practitioners approach the task. (For the procedural rules governing deadlines, extensions, after-final practice, and appeals, see Responding to Patent Office Actions — Strategies for Overcoming Rejections.)

Step one: deconstruct the rejection and test the prima facie case. Read the rejection element by element. Did the examiner identify all the differences between the claims and the art, or quietly skip a limitation? Is the claim construction correct, including the preamble and any means-plus-function or functional limitations? Did the examiner articulate a real rationale with rational underpinning, or merely recite a conclusory label? Did the examiner address the reasonable expectation of success, or assume it? Did the examiner address every dependent claim with significant additional features, or sweep them in by reference? A failure at any of these points is a basis to argue that no prima facie case was made — and the examiner, not the applicant, bears the initial burden. In re Dillon, 919 F.2d at 696, 701; MPEP §§ 2142, 2143, 2145.

There is also a logically prior question that costs nothing to ask: is the cited reference even prior art? Confirm whether AIA or pre-AIA law governs and verify that each reference's date is early enough to qualify against the claimed invention's effective filing date. For non-patent publications, the examiner bears the burden of showing public accessibility before that date. In re Wyer, 655 F.2d 221, 227 (CCPA 1981). A reference cited under the wrong statutory subsection, or one that postdates the claim, can be knocked out before the obviousness analysis even begins.

Step two: decide between arguing and amending. Arguing alone preserves the broadest claim scope but can create prosecution-history estoppel to the extent arguments are read as disclaiming scope. Amending narrows the claim but can decisively distinguish the art. The two are not mutually exclusive; the best responses often amend to add a feature with clear antecedent support in the specification and then argue that the amended claim is patentable, supplying both an amendment-based and an argument-based ground for withdrawal. Any amendment must comply with 37 C.F.R. § 1.121, must find support in the original disclosure, and must not introduce new matter. Where the claims can be saved by argument alone, seek to minimize narrowing amendments and the estoppel they create.

Step three: choose and order the substantive arguments. Lead with the strongest. If the references genuinely cannot be combined without defeating one reference's purpose, that argument may be dispositive. If a reference contains language that discourages the claimed approach, foreground teaching away with a pinpoint quotation. If the rejection rests on "obvious to try" in an unpredictable art, attack the finite-predictable-solutions predicate and emphasize unpredictability and the absence of a reasonable expectation of success. Present arguments in the alternative where appropriate — overcoming the rejection on multiple independent grounds gives the examiner several bases to withdraw and strengthens the record for any later appeal.

Step four: marshal objective evidence and, where warranted, file a declaration. This is where the objective indicia enter prosecution, and they almost always require sworn evidence rather than attorney argument, which carries little weight on factual questions.

A practical fifth move sits alongside these: request an examiner interview. Many obviousness rejections that read as intractable on paper dissolve in a twenty-minute conversation, once the examiner understands which gap in the motivation analysis the applicant intends to press and which claim amendment would resolve it. An interview also lets counsel gauge whether the examiner will accept an argument-only response or insist on an amendment, information that shapes the written reply.

Declarations Under 37 C.F.R. § 1.132

A declaration under 37 C.F.R. § 1.132 is the vehicle for placing factual evidence before the examiner — evidence that attorney argument cannot supply. Rule 1.132 declarations are commonly used to establish:

  • Unexpected results, typically through comparative test data measuring the claimed invention against the closest prior art, with an explanation of why the results would have surprised a POSITA. MPEP § 716.02.
  • Commercial success and nexus, through sales data, market-share evidence, and a showing that the success traces to the claimed features rather than to advertising or unclaimed features. MPEP § 716.03.
  • Long-felt need, failure of others, skepticism, copying, and industry praise, through factual accounts and supporting documents from persons with knowledge. MPEP §§ 716.04, 716.05, 716.06.
  • The level of ordinary skill, the state of the art, and what a POSITA would or would not have expected, through expert declaration testimony. This is frequently the most valuable use of a declaration, because it directly contests the examiner's implicit assumptions about motivation and expectation of success. MPEP § 716.01.

A few practical pointers bear emphasis. The declarant should have demonstrable expertise or personal knowledge; a declaration from the inventor alone may be discounted as self-interested on certain points, so a disinterested expert is often preferable for state-of-the-art testimony. Comparative data must compare against the closest prior art and be commensurate in scope with the claims — a narrow data set supports only narrow claims. And the declaration must state facts, not conclusions: an examiner is entitled to disregard conclusory opinions unsupported by underlying facts. A well-built § 1.132 declaration can convert a losing argument into a winning one, because it shifts the dispute from the realm of attorney rhetoric, where the examiner has the upper hand, into the realm of evidence, where the applicant can build a record.

Worked Example: A Layered Response

Return once more to Acme's water-filtration bottle, now assuming a final rejection under § 103 over References 1 (countertop hollow-fiber filter) and 2 (sports bottle). This is a hypothetical. A strong response might proceed as follows.

First, argue that the examiner failed to make a prima facie case because the rejection recites "simple substitution ... yielding predictable results" without explaining why substituting a countertop-pressure membrane into a suction-driven cap would predictably work — an unsupported conclusion under Nuvasive and Arendi. Second, attack the reasonable expectation of success: nothing in either reference indicates that a hollow-fiber membrane would retain bacterial-filtration performance and adequate flow under cyclical negative pressure. Third, file a § 1.132 declaration from an independent membrane-science expert attaching comparative test data showing that several commercially available membranes failed under suction conditions until Acme developed its specific fiber-bundle geometry — establishing both the absence of a reasonable expectation of success and unexpected results. Fourth, present objective indicia: a declaration documenting that outdoor-recreation companies had sought a reliable drink-through filtration bottle for years (long-felt need), that two named competitors tried and abandoned such products (failure of others), and that a competitor later launched a closely copied bottle (copying) — with a nexus showing that the praise and copying were directed to the claimed drink-through filtration cap rather than to unclaimed bottle aesthetics. A response built on this many independent, evidence-backed grounds is far more likely to produce a withdrawal — or, if it does not, to lay a powerful foundation for appeal to the PTAB.

The Duty of Candor: A Trap Hidden Inside the Obviousness Response

Because obviousness so often turns on the prior art of record, every § 103 response runs alongside the applicant's duty of candor under 37 C.F.R. §§ 1.56 and 11.18(b). Material prior art known to the applicant must be disclosed to the USPTO in an information disclosure statement, and every statement and argument made to overcome a rejection must be accurate, not misleading, and consistent — including consistency with positions taken before other agencies such as the FDA. Withholding a material reference, or mischaracterizing one, to defeat an obviousness rejection can mature into a charge of inequitable conduct that renders the entire patent unenforceable. The interplay is explored in depth in Inequitable Conduct in Patent Prosecution — Navigating the Atomic Bomb of Patent Law. The short version for the practitioner drafting an obviousness response: never win the battle for allowance with an argument that hands an adversary the weapon to destroy the patent later.

Obviousness at the PTAB and in Litigation

The substantive law of obviousness is the same everywhere, but the procedural posture, the burden, and the standard of proof differ sharply across prosecution, the PTAB, and the district court — and those differences drive strategy.

In prosecution before the examiner, there is no presumption of validity; the examiner need only make out a prima facie case, after which the applicant must rebut it, and claims are construed under the broadest reasonable interpretation. The "evidence" is largely documentary — the references — plus any declarations the applicant submits.

At the PTAB in inter partes review (IPR) — a trial-like proceeding in which a third party challenges an issued patent's claims as obvious (or anticipated) over patents and printed publications — the petitioner bears the burden of proving unpatentability by a preponderance of the evidence, a lower bar than the clear-and-convincing standard that applies in court. 35 U.S.C. § 316(e). IPRs are where a large share of contested obviousness battles are now fought, because the lower burden and the technically expert panel make them an attractive forum for challengers. Patent owners in an IPR must take the objective indicia seriously and develop a full evidentiary record, including expert declarations on motivation, reasonable expectation of success, and nexus. The Federal Circuit reviews the Board's obviousness conclusions for legal error and its underlying fact findings for substantial evidence, and it has not hesitated to vacate Board decisions resting on conclusory "common sense" reasoning. In re Nuvasive, 842 F.3d at 1383–85.

In district-court litigation, an issued patent enjoys a statutory presumption of validity, 35 U.S.C. § 282, and an accused infringer asserting obviousness must prove it by clear and convincing evidence — a demanding standard reaffirmed in Microsoft Corp. v. i4i Limited Partnership, 564 U.S. 91 (2011). The accused infringer must prove, as to each challenged claim, the scope and content of the prior art, the differences from the claim, a motivation to combine or modify, and a reasonable expectation of success, Procter & Gamble, 566 F.3d at 994; the patent owner responds by attacking those elements and introducing objective indicia. Because obviousness is ultimately a legal question decided on underlying facts, it is frequently contested at summary judgment and, where fact disputes remain, presented to a jury through competing experts. Notably, a strong prima facie case may support summary judgment of obviousness in some circumstances even against secondary-considerations evidence. Intercontinental Great Brands LLC v. Kellogg North America Co., 869 F.3d 1336, 1344–45 (Fed. Cir. 2017). And claim construction is not a sideshow: how the court construes a disputed term can decide the obviousness question, so both sides should map every proposed construction against every obviousness theory before the Markman hearing.

These cross-cutting standards matter for portfolio strategy. A claim that survives an examiner's prima facie case is not necessarily safe in an IPR, where a motivated challenger with a well-funded expert can mount a far more thorough obviousness case under a lower burden. Building a robust prosecution record — objective-indicia evidence, declarations, and clear statements of why the art does not motivate the combination — pays dividends later if the patent is challenged. For a fuller treatment of how obviousness fits into the broader arc of an infringement case, see our Comprehensive Guide to Patent Infringement Litigation.

Obviousness in Adjacent Doctrines

Obviousness does not live in isolation. A few connections are worth flagging for the practitioner and the curious reader alike.

Design patents. Obviousness for design patents runs on a different track from the utility-patent analysis above. For decades the Federal Circuit applied the rigid Rosen-Durling framework, but in LKQ Corp. v. GM Global Technology Operations LLC, the en banc Federal Circuit overruled that framework and brought design-patent obviousness into closer alignment with the flexible Graham/KSR approach. If your work touches industrial design, see our dedicated analysis, The LKQ Decision — A Seismic Shift in Design Patent Obviousness Analysis.

Subject-matter eligibility. Section 103 is distinct from the § 101 eligibility inquiry — whether the claim is directed to patent-eligible subject matter at all — but the two interact, particularly for software and business-method inventions, where examiners frequently issue both kinds of rejection in the same Office action. A claim element that supplies the "inventive concept" for eligibility purposes may also be the feature that defeats obviousness, and vice versa. For strategies on the eligibility side, see Patent Eligibility After Alice — Strategies for Protecting Software and Business Method Innovations.

Freedom to operate. Obviousness is not only a sword for examiners and challengers; it is also a tool for companies clearing a path to market. When a competitor's patent threatens a planned product, counsel often analyzes whether the patent's claims are vulnerable to an obviousness invalidity attack as part of a freedom-to-operate or invalidity opinion. The same Graham/KSR framework that governs prosecution governs that analysis. See Conducting Freedom-to-Operate Analysis for New Products.

Key Takeaways

  • Obviousness is the highest hurdle in patent law and the most common ground of rejection and invalidation. It asks whether the claimed invention as a whole would have been obvious to a person of ordinary skill before the effective filing date.
  • The Graham framework governs: scope and content of the prior art, differences from the claims, the level of ordinary skill, and the objective indicia of nonobviousness — all weighed together, not sequentially.
  • KSR killed rigid TSM but not the motivation requirement. Motivation may now be drawn from common sense, market forces, and predictable variations, but the examiner or challenger must still supply "articulated reasoning with some rational underpinning." Conclusory "common sense" does not survive appeal.
  • A prima facie case requires three things: identification of the differences, an articulated reason to combine or modify, and a reasonable expectation of success. Testing whether the case was properly made — and whether the reference is even prior art — is the most efficient first line of defense.
  • The substantive rebuttals — attacking the motivation to combine, negating the reasonable expectation of success, teaching away, non-analogous art, change in principle of operation, loss of beneficial properties, and lack of an enabling disclosure for the proposed combination — are most powerful when layered and supported by pinpoint citations.
  • Objective indicia are "often the most probative" evidence of nonobviousness, but they live or die on nexus. Commercial success, long-felt need, failure of others, skepticism, copying, praise, licensing, and unexpected results must be tied to the merits of the claimed invention.
  • In prosecution, evidence beats argument. A well-built declaration under 37 C.F.R. § 1.132 — comparative data, expert testimony on the state of the art, and nexus evidence — can convert a losing position into a winning one.
  • Mind the duty of candor. Never overcome an obviousness rejection with an argument or omission that exposes the patent to an inequitable-conduct attack.
  • Burden and standard shift dramatically across forums: examiner prima facie case in prosecution, preponderance of the evidence at the PTAB, and clear and convincing evidence in district court. Build the record early.

Frequently Asked Questions

What is the difference between anticipation and obviousness? Anticipation under § 102 requires that a single prior-art reference disclose every element of the claim, arranged as claimed. Obviousness under § 103 permits a combination of references, or a single reference modified in light of ordinary skill, and asks whether the differences between the claim and the prior art would have been obvious to a person of ordinary skill. Anticipation is binary; obviousness is a judgment about whether the advance was real.

Does KSR mean that any combination of known elements is obvious? No. KSR held that predictable variations and combinations yielding predictable results are likely obvious, and that motivation need not be explicit. But the Supreme Court reaffirmed that obviousness is not proven merely by showing that each element was individually known, and the Federal Circuit continues to require an articulated, evidence-supported reason to combine and a reasonable expectation of success. Conclusory assertions fail.

How strong does "teaching away" evidence have to be? Strong and specific. A reference teaches away only when it would actually discourage a person of ordinary skill from the claimed path or lead them in a divergent direction. Merely disclosing an alternative, or expressing a general preference for a different approach, is not teaching away. The best showings rest on explicit criticism of the claimed approach, quoted verbatim.

What is the "nexus" requirement, and why does it defeat so many secondary-considerations arguments? Nexus is the required connection between objective evidence (such as commercial success) and the merits of the claimed invention. Success that flows from advertising, brand strength, market power, or unclaimed features proves nothing about obviousness. Where the product is coextensive with the claim, nexus is presumed; where the product has significant unclaimed features, the patentee must affirmatively prove the connection. Many otherwise compelling commercial-success stories fail for lack of nexus.

When should I file a declaration under 37 C.F.R. § 1.132 during prosecution? Whenever your strongest arguments rest on facts that attorney argument cannot establish — unexpected results, the state of the art, what a person of ordinary skill would have expected, commercial success, long-felt need, failure of others, skepticism, or copying. Comparative data should be measured against the closest prior art and be commensurate in scope with the claims, and an independent expert is usually more persuasive than the inventor alone.

Why is it harder to invalidate a patent for obviousness in court than at the PTAB? In district court, an issued patent is presumed valid and the challenger must prove obviousness by clear and convincing evidence. At the PTAB in an inter partes review, the petitioner need only prove unpatentability by a preponderance of the evidence — a lower burden — which is one reason challengers increasingly favor the PTAB for obviousness disputes.

Can an obviousness rejection ever be answered with argument alone, without amending the claims? Yes, and often it should be, because amendments narrow scope and can create prosecution-history estoppel. If the prima facie case is defective — a missing limitation, a conclusory rationale, no reasonable expectation of success — argument alone may carry the day. But where the art is genuinely close, a targeted amendment supported by the specification, paired with argument, is frequently the surer route.

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This article is provided by mclaw.io for general informational purposes only and does not constitute legal advice, nor does it create an attorney-client relationship. Obviousness determinations are intensely fact-specific and depend on the particular claims, prior art, and record at issue. Readers facing an actual obviousness rejection or invalidity challenge should consult qualified patent counsel about their specific circumstances.