The Federal Circuit’s precedential opinion in Arendi S.A.R.L. v. Apple Inc., et al., Case No. 2015-2016 (Aug. 10, 2016) is instructive on the limits of “common sense” in an obviousness analysis. The opinion is also an example of what appears to be a growing trend of the Federal Circuit reminding the Board that it must support its findings with a full and reasoned analysis. See also “PTAB Reminded of Its Obligations Under the Administrative Procedures Act” (published Aug. 15, 2016 at

At issue on appeal was the Board’s determination in an IPR proceeding that certain claims in Arendi’s patent, U.S. Patent No. 7,917,843, were unpatentable as obvious based on a single reference. Specifically, the question was whether the Board erred by relying on “common sense” to supply a missing claim limitation as part of its single-reference obviousness analysis.

The court began with a tutorial on the appropriate use of “common sense.” First, it explained that “common sense” is usually limited to providing a motivation to combine references, rather than to supply a missing limitation. Second, when “common sense” is used to supply a limitation, that limitation should be “unusually simple.” Slip op. at 10. Third, the court warned that “common sense” “cannot be used as a wholesale substitute for reasoned analysis and evidentiary support.” Id. at 11. Based on its prior precedent, the Federal Circuit concluded:

[W]hile ‘common sense’ can be invoked, even potentially to supply a limitation missing from the prior art, it must still be supported by evidence and a reasoned explanation. In cases in which ‘common sense’ is used to supply a missing limitation, as distinct from a motivation to combine, moreover, our search for a reasoned basis for resort to common sense must be searching. And, this is particularly true where the missing limitation goes to the heart of an invention.

Id. at 12-13.

Applying these principles, the court concluded that the Board erred by resorting to “common sense” in this case. The court explained that the record contained only “conclusory statements and unspecific expert testimony,” which was “particularly problematic” as a “key limitation” was missing from the prior art. Id. at 19. Rather than remanding the case for further Board analysis, the court reversed the Board’s decision, noting “there is nothing in the record to support the Board’s conclusion that supplying the missing limitation would be obvious”. Id. at 20.

While Arendi will likely limit the use of “common sense” in future Board opinions, it may have a greater impact as another example of the Federal Circuit emphasizing the need for the Board to provide a reasoned analysis supported by the record evidence.