What Is Obviousness?

Obviousness is the most common reason patent claims are rejected during examination and the most common ground for invalidating patents after grant. An invention is obvious if a person of ordinary skill in the relevant technical field would have found it straightforward to arrive at the claimed invention by combining or modifying what was already known.

Novelty asks: has this exact thing been done before? Obviousness asks a harder question: even if this exact thing hasn't been done, would it have been an unremarkable next step for someone working in this area?

The Legal Framework

United States

US obviousness law is built on 35 U.S.C. § 103 and the Supreme Court's framework in Graham v. John Deere (1966), which requires four inquiries:

1. Scope and content of the prior art. What was known in the field?
2. Differences between the prior art and the claims. What is the gap between what was known and what is claimed?
3. Level of ordinary skill in the art. How sophisticated is the typical practitioner?
4. Secondary considerations of non-obviousness. Also called "objective indicia" — commercial success, long-felt but unresolved need, failure of others, unexpected results, copying by competitors, and professional acclaim.

The Supreme Court's decision in KSR v. Teleflex (2007) expanded the scope of obviousness by rejecting the rigid "teaching, suggestion, or motivation" (TSM) test that had previously limited examiners to combining prior art references only when one reference explicitly suggested the combination. After KSR, examiners can rely on common sense, market forces, design incentives, and the general knowledge of a skilled person to argue that a combination would have been obvious.

Europe (EPO)

The EPO applies the problem-solution approach: identify the closest prior art, determine the technical problem that the invention solves relative to that prior art, and assess whether the claimed solution would have been obvious to the skilled person. The EPO approach is more structured than the US framework but reaches similar conclusions in most cases.

Other Jurisdictions

China, Japan, South Korea, India, and most other major patent offices apply inventive step requirements that are broadly comparable — though specific thresholds and analytical frameworks differ. Japan and Korea tend toward the EPO's structured approach; China's analysis has converged with international standards in recent years.

How Obviousness Rejections Work

An examiner identifies two or more prior art references that, when combined, teach every element of the claimed invention. The examiner argues that a skilled person would have been motivated to combine them and that the result would have been predictable.

The applicant can respond by arguing that the combination would not have been obvious — that there was no motivation to combine, that the references teach away from the combination, that the result was unexpected, or that secondary considerations support non-obviousness.

Secondary Considerations: Your Best Defence

When the technical argument is close — when the prior art is relevant but not identical — secondary considerations often determine the outcome:

Commercial success. If the invention achieved significant commercial success that prior art products did not, this suggests the invention was not an obvious next step. The success must be attributable to the claimed features, not to marketing or unrelated factors.

Long-felt but unsolved need. If the problem existed for years and skilled practitioners failed to solve it, this supports non-obviousness. The longer the need persisted, the stronger the argument.

Failure of others. If others tried and failed to solve the same problem using similar approaches, the claimed solution is less likely to have been obvious.

Unexpected results. If the claimed combination produces results that a skilled person would not have predicted — higher efficiency, unexpected synergy, a different mechanism — this weighs against obviousness.

Copying by competitors. If competitors copied the patented invention rather than designing around it, this suggests the invention was not an obvious alternative that competitors could have arrived at independently.

What This Means for Inventors

Obviousness is the rejection you are most likely to face. Prepare for it:

Conduct a thorough prior art search before filing, so you understand the landscape your claims must navigate. Draft claims that emphasise what is genuinely inventive — not just different, but non-obvious to a skilled person. Document any unexpected results, commercial success, or evidence of long-felt need. And keep records of competitors' reactions to your invention — copying is powerful evidence of non-obviousness.

Sources

1. 35 U.S.C. § 103 — Obviousness — US statutory basis for obviousness rejections
2. MPEP § 2141 — Obviousness Guidelines — USPTO examination guidelines including Graham factors and TSM test
3. EPC Article 56 — Inventive Step — European equivalent of obviousness requirement
4. EPO Guidelines — Inventive Step — EPO problem-solution approach to inventive step assessment