Understanding Large Temporal Networks and Spatial Networks: Exploration, Pattern Searching, Visualization and Network Evolution

5Citation Patterns in Temporal United States Patent Data

Schumpeter (1942) identified innovation as a primary driver of economic growth. Integral to innovation is the creation of new machines, new methods of production, and new products by inventors. Throughout human history, new technologies have transformed societies (Lenski 1966). Economists have long studied links between innovation, technological change, and economic development. The importance of particular inventions depends on the consequences of implementing them. Estimating the magnitude of technological changes, let alone establishing their wider societal impacts, is extremely hard. Inventions are intrinsic parts of technological change with many inventions being patented. Since the pioneering work of Schmookler (1966), patents have been studied¹ to gain more insight into technologically driven economic and social changes (see Griliches (1984, 1990); Trajtenberg (2002)). Patents differing in importance provide indirect evidence regarding large and small sources of the impact of technology on economic change. One potential indicator of a patent's importance is the extent to which it is used (cited) by later patents. This had led to the development of indices of the importance of patents (e.g. Carpenter et al. (1981); Trajtenberg (2002)). We do not dispute the value of this line of work but adopt a complementary approach. Consistent with the objectives of this book, we try to understand the structure of patent networks ...