The KSR Decision

Section 103 of the patent code states that a patent may not be obtained if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which the subject matter pertains. Typically, an obviousness rejection under Section 103 is based either on a combination of two or more prior art references, or on a modification of a single prior art reference.

In the recent decision of KSR International Co. v. Teleflex Inc., the Supreme Court arguably lowered the burden on a patent examiner in rejecting a patent application as being obvious. More specifically, the Supreme Court rejected the rigid “teaching, suggestion, or motivation” test (TSM test), which required the patent examiner to show a teaching, suggestion, or motivation in the prior art to modify, or combine, the prior art teachings in the manner claimed by the patent applicant. Instead, the Court returned to the more flexible approach set forth in the long-standing Supreme Court case of Graham v. John Deere Co. of Kansas City, which set forth four factors for applying Section 103. These factors, which have come to be known as the “Graham Factors,” include: (1) the scope and content of the prior art; (2) the level of ordinary skill in the art; (3) the differences between the claimed invention and the prior art; and (4) objective evidence of nonobviousness (also known as “secondary considerations”).

The Increased Importance of Secondary Considerations

In KSR, the Supreme Court emphasized the importance of secondary considerations in determining obviousness, since they “give light to the circumstances surrounding the origin of the subject matter sought to be patented.” In Ortho-McNeil Pharma., Inc. v. Mylan Labs., Inc., a case subsequent to KSR, the Federal Circuit found the secondary considerations to be “[o]f particular importance beyond the prima facie analysis” and “not just a cumulative or confirmatory part of the obviousness calculus but . . . independent evidence of nonobviousness.” 520 F.3d 1358, 1365 (Fed. Cir. 2008). Therefore, it is clear that the secondary considerations have gained importance in the post-KSR era.

Evidence of secondary considerations, when available, often works in favor of proving patentability. Therefore, in view of KSR’s rejection of the rigid TSM test, and its emphasis on the importance of secondary considerations in determining obviousness, it can be especially valuable in post-KSR patent practice to introduce evidence of secondary considerations during prosecution of a patent application.

What Are the Secondary Considerations?

Secondary considerations are real-world evidence about the invention. The Graham opinion set forth three, non-exhaustive examples of secondary considerations. These were whether the invention achieved commercial success, whether the invention satisfied a long-felt but unsolved need, and failure of others. Cases subsequent to Graham set forth other examples of secondary considerations, such as praise for the invention, copying of the invention, unexpected results, and skepticism or disbelief before the invention.

How Do You Introduce Evidence of Secondary Considerations?

In the context of patent prosecution, evidence of the secondary considerations is typically introduced through inventor declarations, for example, in response to an obviousness rejection from the U.S. Patent and Trademark Office. Alternatively, evidence showing secondary considerations can be described directly in the patent application itself. In a litigation context, evidence of secondary considerations can be introduced in a number of ways, including expert testimony.


After KSR, secondary considerations are more valuable than ever in proving nonobviousness. Therefore, inventors, in-house counsel, and prosecuting attorneys are encouraged to keep secondary considerations in mind during all phases of patent prosecution, for example, when deciding whether to file a patent application, when preparing the application, and when responding to rejections from the U.S. Patent and Trademark Office. In addition, favorable evidence regarding secondary considerations should be used when defending a challenge to an issued patent’s validity, for example, during a Reexamination proceeding in the U.S. Patent and Trademark Office, or during a litigation in the district courts. Strong evidence of secondary considerations, such as commercial success, praise, or copying, may play a crucial role in obtaining and/or defending your patents.