Defining a Software Patent

There is no universally accepted way to define what is or is not a software patent. In fact, much of the debate around software patents includes arguing over the definition. For example, some would consider a patent covering a “computer system” with generic hardware that performs some function to be a software patent. Some would argue only patents that can be infringed by software alone are truly “software patents.”

In their article, An Empirical Look At Software Patents (PDF), James Bessen and Robert Hunt devote significant attention to the issue and formulate their own search algorithm for identifying software patents, which is:

(“software” in specification) OR (“computer” AND “program” in specification)

AND (utility patent excluding reissues)

ANDNOT (“chip” OR “semiconductor” OR “bus” OR “circuit” OR “circuitry” in title) ANDNOT (“antigen” OR “antigenic” OR “chromatography” in specification)

Of course, as Bessen and Hunt admit, their algorithm produces both false negatives and false positives, but they found it to be more accurate than other methods. Unless otherwise noted, the Bessen Hunt algorithm is the general method used by the Software Patent Watch to identify software patents.