SUBMARINES AND TECHNOLOGICAL INNOVATION: U.S. CONTINUATION PATENTING IN SOFTWARE AND BIOTECHNOLOGY TECHNOLOGIES IN THE 1980s AND 1990s

This chapter examines the role of “continuations” (procedural revisions of patent applications) within software patents and overall patenting in the United States during 1987–1999. Our research represents the first effort of which we are aware to analyse data on continuations in software or any other patent class, and as such provides information on the effects of 1995 changes in the U.S. patent law intended to curb “submarine patenting.” Our analysis of all U.S. patents issued 1987–1999 shows that the use of continuations grew steadily in overall U.S. patenting through 1995, with particularly rapid growth in continuations in software patenting. Sharp reversals in these growth rates after 1995 suggest that changes in the U.S. patent law were effective. Continuations were used more intensively by packaged-software firms prior to the effective date of the 1995 changes in patent law than by other patentees, and both software and non-software patents subject to continuation tend to be more valuable.