The Supreme Court’s April 30, 2007 decision in KSR International Co. v. Teleflex Inc. strikes at the heart of the U.S. patent statute – Section 103’s criteria for determining obviousness – and as such has potentially wide-ranging implications. The potential impact will be most pronounced for patentees who, to win approval from the U.S. Patent and Trademark Office, relied heavily on non-obviousness arguments that have now been rejected or criticized by the Supreme Court. As explained more fully below, this includes arguments based on: (a) the absence of an express teaching, suggestion, or motivation to make the claimed invention, (b) a dismissal of prior art because it was not directed to the same problem as that solved by the invention, and (c) a dismissal of evidence on grounds that it merely showed that the claimed invention was “obvious to try.” The amount of damage done to these patentees will be directly proportional to the extent to which their arguments for patentability depended exclusively on the disfavored criteria.

For the great majority of issued patents, the only significant threat posed by KSR will be its general sentiment that patents have been too easily granted and that they should therefore be more closely scrutinized. In large part the Supreme Court was reacting to an already existing public disdain for weak patents, and it is therefore difficult to predict the precise role KSR will have, if any, in causing increased scrutiny in the marketplace or in the courts. Furthermore, to the extent that the decision is cited as cause for additional scrutiny, good lawyers will in most cases be able to minimize the damage by drawing from the large body of non-obviousness arguments that remain unfazed by KSR. Indeed, many of the seemingly harsh pronouncements in KSR had already been expressed in the same or similar contexts in other precedential decisions, and skillful lawyers have for many years hedged their bets by relying in whole or in part on arguments that do not now run afoul of KSR.

Patent applicants will likewise need to adjust to the ramifications of KSR. Where applications are nearing issuance, applicants are well advised to review past arguments as soon as possible to identify real or perceived conflicts with KSR, and where appropriate, augment the record with alternative evidence and reasons for allowance. As discussed below, KSR will tend to shift the burden of proof on obviousness to the patentee in cases where all elements of a claimed invention are separately shown in a number of prior art references. In these cases patent applicants may find it necessary to present evidence, perhaps including expert opinion, to show technological distinctions, unexpected results, long-felt unsolved need, commercial success, and the like, and the added evidentiary showings may in turn result in significantly increased prosecution expense. Further, the cost of successful prosecution may in some cases become more time-consuming and expensive due to KSR’s clarification that relevant prior art includes prior art directed to problems analogous to the problem faced by the inventor, not just prior art directed to the problem itself.

Separating perception from reality – what has KSR really changed?

Several popular press accounts of KSR imply that it forebodes a sea change in the way patentability and patent validity will be assessed. But in reality KSR leaves large swaths of obviousness law intact. It signals a more stringent obviousness analysis with respect to use of the teaching, suggestion, motivation test (“TSM test”), the scope of the prior art, and the “obvious to try” rationale, but its holdings are measured, and often in sync, with already established precedent from the courts and the existing practice before the U.S. Patent and Trademark Office. Further, some of its pronouncements lack clarity and will likely be subject to creative interpretation in subsequent Federal Circuit decisions.

The following summarizes KSR’s likely impact on various obviousness criteria:

The Graham factors for assessing obviousness. The Supreme Court affirmed and fully deferred to a cornerstone of obviousness law, its earlier 1966 decision in Graham v. John Deere, saying that the four obviousness factors Graham recites – scope and content of the prior art, differences between the art and the claims at issue, level of ordinary skill, and secondary considerations – “define the controlling inquiry.” Arguably KSR increases the stature of the so-called “secondary considerations” – commercial success, long-felt but unsolved needs, failure of others, etc. – since it suggests that the inquiry into the existence of secondary considerations need not be left to the last (“While the sequence of these questions might be reordered in any particular case, the factors continue to define the inquiry that controls.” Opinion at p.2)

The TSM test. The Federal Circuit has for many years relied on the TSM test to assess obviousness. The test has not always been applied uniformly, but it has generally required that an examiner or patent challenger establish that there was something in the prior art that taught, suggested, or motivated one skilled in the art to make the claimed invention. In KSR, the Federal Circuit had held that the district court had not applied the TSM test strictly enough, since it failed to make findings as to the specific understanding or principle that would have motivated one with no knowledge of the invention to make it. The Supreme Court rejected the Federal Circuit’s rigid application of the test and concluded that a patent can be found invalid even when the TSM test is not satisfied, but recognized that the test “captures a helpful insight.” Summarizing, the Court said:

“There is no necessary inconsistency between the idea underlying the TSM test and the Graham analysis. But when a court transforms the general principle into a rigid rule that limits the obviousness inquiry…it errs.” Opinion at p.15

The Supreme Court’s rejection of the TSM test as a requirement for showing obviousness is the most significant aspect of the KSR decision. Where previously a patent applicant or patentee could sometimes rely on the test to defend against an obviousness challenge based on unconnected teachings in the prior art, some examiners and courts may now be inspired to require the applicant or patentee to affirmatively show why the combination of teachings would not have been obvious. This impact of KSR is limited by the fact that many patent examiners and courts had already been applying the test liberally, for example by finding that a motivation to combine was implicit in prior art teachings or within the knowledge generally available to one of ordinary skill. The impact is also tempered by seemingly contradictory statements in KSR itself. In order to evaluate whether a given combination was obvious, the Supreme Court says the fact finder must “determine whether there was an apparent reason to combine the known elements in the fashion claimed by the patent at issue,” and it requires that, “[t]o facilitate review, the analysis should be made explicit.”

Opinion at p.14 

Scope of the relevant prior art. The Supreme Court criticized the Federal Circuit’s assessment of the scope of the prior art saying the Federal Circuit had taken the overly narrow view that courts and patent examiners should look only to the problem the inventor was attempting to solve and only to prior art addressing that problem. The Supreme Court said:

“Common sense teaches, however, 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.”

Opinion at p.16-17

This aspect of the decision is helpful in clarifying the law, and it will encourage patent examiners and courts to look at a broader range of prior art teachings. For some inventions the broader consideration of prior art will result in a denial or invalidation of patent rights. However, the scope of prior art previously considered by examiners and courts has typically included prior art that was not directly related to the problem addressed by the invention under consideration.

For this reason the actual impact of KSR in this regard is limited.

Obvious to try. The Supreme Court disapproved of the Federal Circuit’s treatment of the “obvious to try” exception to obviousness, whereby the Federal Circuit had reasoned that teachings in the prior art were merely evidence that one skilled in the art would have found the claimed invention obvious to try, and not necessarily obvious. According to the Supreme Court:

“When there is a design need or market pressure to solve a problem and there are a finite number of identified, predictable solutions, a person of ordinary skill has good reason to pursue the known options within his or her technical grasp.”

Opinion at p.17

In practice, few patents have been granted or defended solely on the basis that evidence showed an obviousness to try and not obviousness per se, and the impact of KSR on this point is therefore limited. Further, the Supreme Court’s rationale for rejecting the Federal Circuit’s reliance on the “obvious to try” distinction has been used by courts prior to KSR to discount and reject patentee arguments of this nature.

Combinations and unpredictable results. The decision states that a claimed combination of “familiar elements” according to known methods is “likely to be obvious” if it does not yield unpredictable results, but it stops short of requiring a showing of unpredictability any time elements of a claimed combination are found in the prior art. However, when the claimed invention involves a “simple substitution of one known element for another or the mere application of a known technique to a piece of prior art ready for the improvement,” the Supreme Court said that a court “must ask whether the improvement is more than the predictable use of prior-art elements according to their established functions.” Opinion at p.13-14. It is unlikely that courts and examiners will interpret the Supreme Court’s decision in KSR to require a showing of unpredictability in all but the simplest cases of substitution, and as such, the decision is likely to have little if any affect on the previously existing role of unpredictability in obviousness determinations.

Litigating obviousness after KSR

We believe KSR will have two significant impacts on litigation: (1) litigation will be more costly, and (2) district court judges may give less deference to Federal Circuit precedent. Costs will increase because KSR invites more historic and expert evidence on Graham factors – notably secondary considerations – and in some cases prior art outside the immediate field of use of the invention. With respect to Federal Circuit deference, we expect district court judges will draw more from the recent and more frequent Supreme Court pronouncements than from Federal Court precedent, and will more confidently craft decisions based on their sense of practicality and common sense rather than parameters laid down by the appellate court.


KSR helps clarify important aspects of obviousness law but does not, as some have suggested, signal a dramatic shift in the way U.S. patent rights will be accorded. KSR’s impact will likely be most pronounced for patentees who relied too heavily on the Federal Circuit’s TSM test or otherwise analyzed evidence before the Patent and Trademark Office in a way that directly contradicts the Supreme Court’s pronouncements in KSR. For all other patentees the biggest challenge will be KSR’s anti-patent tone, but this challenge can largely be met by refocusing on the large body of non-obviousness arguments unaffected by KSR. Present and future patent applicants will likewise need to retool their arguments in gaining patent issuance. Applicants may face added expense in doing so, and some limited number of marginally patentable inventions may fail the post-KSR test. The KSR decision will in general foster a more rigorous and thorough examination of patent claims in the Patent Office and in the courts, but for the most part the established way of determining patent rights will survive.

The Supreme Court's KSR opinion is available at and 127 S. Ct. 1727.