Non-Obviousness · § 103 · Patent Examination
KSR and the Obviousness Standard
KSR International v. Teleflex (2007) made patent obviousness easier to find by replacing a rigid test with a flexible standard. Nearly every § 103 office action and invalidity defense now cites it.
The bottom line
Before KSR, obviousness required finding an explicit teaching in the prior art to make the combination. After KSR, a patent is obvious whenever a POSITA with ordinary creativity would have combined known elements to solve a known problem with a reasonable expectation of success — no explicit suggestion required.
The case
KSR International Co. v. Teleflex Inc. (2007)
Teleflex held a patent on a vehicle gas pedal assembly that combined an adjustable pedal with an electronic sensor at a specific location on the pedal. KSR made a competing adjustable pedal and was sued for infringement. KSR argued the claims were obvious over the prior art.
The Federal Circuit, applying TSM, found for Teleflex — there was no explicit teaching in the prior art to combine adjustable pedals with electronic sensors. The Supreme Court reversed unanimously, holding TSM too rigid.
The holding (unanimous, 2007)
A person of ordinary skill is not an automaton — they are presumed to have ordinary creativity, common sense, and awareness of the relevant prior art. The TSM test, while a helpful insight, is not the sole standard for obviousness. When there is a design need and a finite number of identified, predictable solutions, a POSITA would have had reason to combine the elements regardless of explicit suggestion. Teleflex's pedal claim was obvious.
The immediate impact: the USPTO issued KSR Examination Guidelines (2007) codifying seven rationales for obviousness. § 103 rejections increased substantially, and courts invalidated far more patents on obviousness grounds in the years following.
The framework
Graham v. John Deere — the four factual inquiries
KSR reaffirmed the Graham v. John Deere (1966) framework as the controlling structure. Obviousness is a legal conclusion based on underlying facts determined under four inquiries:
Scope and content of the prior art
What was publicly known in the field before the invention's effective filing date — patents, publications, public use, prior sales, and any other prior art.
Differences between the prior art and the claims
Exactly what the claimed invention adds beyond what was already known. This is the delta the examiner must explain is obvious.
Level of ordinary skill (POSITA)
The skill level of a hypothetical person of ordinary skill in the pertinent art at the time of the invention — education, experience, and knowledge they would typically have.
Secondary considerations (objective indicia)
Commercial success, long-felt unsolved need, failure of others, unexpected results, industry praise, and copying by competitors. Must show nexus to the claimed features.
KSR rationales
The seven rationales for combining prior art
The USPTO's 2007 KSR Guidelines identified seven rationales that can support an obviousness finding. Examiners must cite one or more of these when making a § 103 rejection. None requires an explicit statement in the prior art that one should combine the references.
Combination of known elements by known methods
Combining prior art elements according to known methods to yield predictable results. If each element of the claim is known in the prior art and combining them would produce the claimed invention predictably, the claim is obvious.
Example
A GPS device + a turn-by-turn voice navigation algorithm both existed. Combining them predictably yields a navigation system — obvious.
Simple substitution
Substituting one known element for another to obtain predictable results. If a known element can be swapped for another known element and the result would be predictable to a POSITA, the substitution is obvious.
Example
Replacing a mechanical governor with an electronic one in a known machine, where electronic governors were known to work the same way — obvious substitution.
Known technique improving similar devices
Using a known technique to improve similar devices, methods, or products in the same way. If the technique was routinely applied to improve related devices, applying it to the claimed device is likely obvious.
Example
Applying a known friction-reducing coating that was used on surgical tools to identical instruments — obvious if the coating was known to work in analogous contexts.
Known technique applied to known device ready for improvement
Applying a known technique to a known device (method or product) that is ready for improvement, and a POSITA would have had reason to apply the technique. The device need not have previously used the technique.
Example
Applying a known software encryption technique to a known e-commerce checkout system that lacked encryption — obvious if the need for security was recognized.
Obvious to try
Choosing from a finite number of identified, predictable solutions with a reasonable expectation of success. If the prior art identified the problem and pointed toward a limited set of solutions, trying each is obvious.
Example
Prior art identifies 3 known antibody structures that bind a receptor. Claiming one of them as a therapeutic agent may be obvious if each was a predictable candidate.
Design need / market pressure
A design need or market pressure to solve a problem, and a finite number of predictable solutions, renders a solution obvious even without explicit suggestion in the prior art.
Example
Market demanded lighter laptops; engineers knew reducing battery size or using lighter materials were the finite obvious solutions.
TSM in the prior art
The original TSM test still applies: an explicit teaching, suggestion, or motivation in the prior art to make the claimed combination. KSR did not eliminate TSM — it supplemented it with the above rationales.
Example
A prior art reference explicitly suggests adding feature X to device Y to improve performance Z — directly teaches the combination.
Strategy
How to overcome a KSR obviousness rejection
Attack the rationale — show the combination is not predictable
The most powerful response. If the examiner argues rationale #1 (known elements, known methods), show that combining the references would NOT yield predictable results — the combination would produce unexpected behavior, or would require modification of one reference in a way the reference itself teaches away from.
Show the prior art teaches away from the combination
If a prior art reference explicitly discourages the combination the examiner relies on — warning of problems, showing the approach was abandoned, or pointing toward a different solution — that teaching away is strong evidence the combination was not obvious.
Challenge the POSITA level
If the examiner's POSITA is too skilled (attributing expert-level knowledge to an ordinary practitioner), the obviousness argument may be overstated. A POSITA with the correct skill level may not have been motivated or capable of making the combination.
Present secondary considerations with nexus evidence
Commercial success, long-felt need, and failure of others are most powerful when the evidence shows the market recognized the problem for years and skilled workers failed to solve it before the invention. A strong declaration from the inventor or industry expert, combined with market data, can shift the balance.
Amend claims to distinguish over the combination
If the prior art combination clearly covers the current claim, amend to add a limitation that the combination does not teach. Be strategic — the amendment must narrow the claim only as much as necessary, and beware of prosecution history estoppel.
Argue unexpected results
If the claimed combination yields a result that is quantitatively or qualitatively different from what a POSITA would have expected based on the prior art elements independently, unexpected results are powerful evidence of non-obviousness. Requires a declaration with comparative data.
FAQ
KSR obviousness questions
What did the KSR case change about patent obviousness?
KSR International Co. v. Teleflex Inc. (2007) unanimously rejected the Federal Circuit's rigid application of the Teaching-Suggestion-Motivation (TSM) test for obviousness. Under TSM, an examiner or court could only find a patent obvious if there was an explicit teaching, suggestion, or motivation in the prior art to combine the references. KSR held that the TSM test, while a valid consideration, was not the only way to establish obviousness. The Supreme Court adopted a flexible, expansive standard: a POSITA is presumed to have ordinary skill and common sense, to be aware of the relevant prior art, and to be capable of combining known elements for their known purposes when there is a recognized problem and a finite number of known solutions. This made it significantly easier for examiners and courts to invalidate patents as obvious.
What are the Graham v. John Deere factors for obviousness?
The Supreme Court in Graham v. John Deere Co. (1966) established the factual framework for determining obviousness under § 103, which KSR reaffirmed as the controlling framework: (1) Scope and content of the prior art — what was known in the field before the invention's effective filing date; (2) Differences between the prior art and the claimed invention — what exactly the claimed invention adds beyond what was already known; (3) Level of ordinary skill in the pertinent art (POSITA) — what a person of ordinary skill could be expected to know and do; (4) Secondary considerations (objective indicia of non-obviousness) — commercial success, long-felt but unsolved need, failure of others, unexpected results, industry praise, copying by competitors, licensing. The first three Graham factors are factual determinations; the ultimate question of obviousness is a legal conclusion.
What are the KSR rationales for combining prior art?
KSR identified several rationales — beyond explicit TSM — that can support an obviousness finding: (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 similar devices in the same way; (4) Applying a known technique to a known device/method that is ready for improvement; (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 may prompt variation in another, if the variation is predictable to a POSITA; (7) Some teaching, suggestion, or motivation in the prior art that would have led a POSITA to modify the prior art to arrive at the claimed invention. The USPTO's 2007 KSR Guidelines codified these into examination procedure.
What is 'obvious to try' and when does it apply?
After KSR, 'obvious to try' can support an obviousness rejection when: (1) there is a recognized problem or need in the art; (2) there are a finite number of identified, predictable solutions; and (3) a POSITA would have had a reasonable expectation that trying each of the solutions would have a reasonable expectation of success. The key limits: 'obvious to try' does not apply when there are a vast number of potential solutions with no way to predict which will work (the Federal Circuit called this an 'uncertain sea of possibilities'), or when the prior art taught away from the combination. Biotech and pharmaceutical patents are most often challenged on 'obvious to try' grounds — if prior art identified a compound class and the claimed compound is one of a finite set of obvious variants, the compound may be invalid as obvious to try.
How do secondary considerations (objective indicia) help overcome an obviousness rejection?
Secondary considerations are objective indicia of non-obviousness that can rebut an examiner's or court's prima facie case of obviousness. The most powerful: (1) Commercial success — must show the success is due to the claimed features, not to marketing, brand recognition, or pricing; (2) Long-felt but unsolved need — the problem existed in the art for years and others attempted but failed to solve it; (3) Failure of others — skilled workers in the field tried and failed to achieve the invention; (4) Unexpected results — the claimed invention achieves results that would not have been expected by a POSITA based on the prior art; (5) Copying — a competitor deliberately copied the patented invention rather than designing around it; (6) Praise from experts — industry recognition that the invention solved a difficult problem. For secondary considerations to carry weight, there must be a nexus between the secondary consideration evidence and the claimed features — commercial success from a feature that is not claimed doesn't help.