Patent Citation Cycles

A BASIC DESCRIPTION OF PATENT CITATION cycles is provided for 1,100 major companies and organizations covered by the TECH-LINEsM database. The average U.S. patent has five to six “references citedU.S. patent documents.” The properties of these patent citations are shown to vary widely from one technology to another. For example, patents in Office Computing and Accounting, a relatively hot area, are cited almost three times as frequently as patents in Organic Chemicals, a less active area of patenting. Similarly, technology cycle times vary widely-from five to six years in fast moving electronics areas to twelve to fifteen years in some of the slow moving areas of mechanical technology. Citations to earlier patents peak at patents three to five years old, rather similar to the peak citation time for scientific literature. Since these citation peaks and cycle times are relatively short, and represent the difference between current art and prior art, this indicates, in one sense, that the technological lifetime of an invention may be much shorter than its legal and commercial life times.