See Van Dam et al. (1991).

Personal communication with John R. Lehmann, Deputy Division Director for Computer-Communications Research, National Science Foundation, July 31, 1997.

In 1997, NSF restructured the Advanced Scientific Computing Centers program into the Partnership for Advanced Computation Infrastructure (PACI). Under the PACI program, each partnership operates a leading-edge site that maintains high-end hardware systems that are one or two orders of magnitude more capable than those typically available at a major research university. Nonleading-edge partners are expected to contribute to access, outreach, training, and software development. Two partnerships support two leading-edge centers and over 60 partners. These are the the National Computational Science Alliance, which is anchored by the National Center for Supercomputing Applications in Urbana-Champaign, Illinois, and the National Partnership for Advanced Computational Infrastructure, anchored by the San Diego Supercomputing Center in California.

Invention refers to the creation of new products or processes that meet the test of novelty and utility and are not obvious to experts in the field. Innovation generally refers to the development and application of a new product, process, or service. As a result, patent statistics suffer from a number of shortcomings as a measure of innovation. Patents register new inventions, not innovation. Many inventions are never commercialized, and many innovations are never patented. For example, a firm may decide to keep its innovation a trade secret rather than filing a patent, which requires a disclosure of the operation of the new product, process, or service. Much technological progress emerges from incremental innovation, learning by doing, and adaptation of existing technologies. Patent statistics do not provide any indication of the economic value of the invention patented.

The vast majority of patents do not cite scientific or technical literature; they tend to cite previous patents, demonstrating the degree to which they represent incremental improvements to the state of the art.

The estimates of patents and cited papers contained in this paragraph derive from data provided by Francis Narin and Anthony Breitzman at CHI Research, Inc., in Haddon Heights, N.J.