A “common sense” reason for adding a missing limitation to the prior art to establish obviousness is generally improper unless the limitation is unusually simple and a reasoned analysis is still provided. Here, for example, adding a search operation to detect duplicate entries in an electronic address book out of “common sense” was found to be untenable because this was an important limitation of the claimed invention and the Board’s analysis consisted of mere conclusory statements. “[O]ur cases repeatedly warn that references to ‘common sense’—whether to supply a motivation to combine or a missing limitation—cannot be used as a wholesale substitute for reasoned analysis and evidentiary support, especially when dealing with a limitation missing from the prior art references specified.” This would be a good case to consult and cite in response to an obviousness rejection predicated on common sense.

Background / Facts: The patent on appeal here from inter partes review proceedings at the PTO is directed to an electronic address book database. The claims recite, among other limitations, performing a “search” for duplicate information such as telephone entries when entering a telephone number into the database. It is not disputed that the prior art discloses each limitation of the claimed invention except for performing the search.

Issue(s): Whether it is merely “common sense” to conclude that it would have been obvious to supply the missing limitation to arrive at the claimed invention.

Holding(s): No. “[T]here are at least three caveats to note in applying ‘common sense’ in an obviousness analysis. First, common sense is typically invoked to provide a known motivation to combine, not to supply a missing claim limitation. … Second, … [where] common sense was invoked to supply a limitation that was admittedly missing from the prior art, the limitation in question was unusually simple and the technology particularly straightforward. … Third, our cases repeatedly warn that references to ‘common sense’—whether to supply a motivation to combine or a missing limitation—cannot be used as a wholesale substitute for reasoned analysis and evidentiary support, especially when dealing with a limitation missing from the prior art references specified.” Here, “the search is an important limitation” and a mere “conclusory statement is insufficient to justify a conclusion about ‘common sense.’”

Full Opinion