Was Electricity a General Purpose Technology?

Review of Economics and Statistics, 1999

2000

A survey of recent patentees was conducted to elicit their perceptions regarding the importance of their inventions, the extent of their communication with other inventors, and the relationship of both importance and communication to observed patent citations. A cohort of 1993 patentees were asked specifically about 2 patents that they had cited, and a third "placebo" patent that was similar but which they did not cite. One of the two cited inventors was also surveyed. We find that inventors report significant communication, at least some of which is in forms that suggests spillovers from the cited inventor to the citing inventor. The perception of such communication was substantively and statistically significantly greater for the cited patents than for the placebos. T here is, however, a large amount of noise in citations data; it appears that something like one-half of all citations do not correspond to any perceived communication, or even necessarily to a perceptible technological relationship between the inventions. We also find a significant correlation between the number of citations a patent received and its importance (both economic and technological) as perceived by the inventor.

1997

Research Papers in Economics, 2019

The investigation comprises information about patent citations distributed by different technological domains, which are used to map knowledge flows and to correlate these flows with the evolution of countries' competences. Specifically, the analysis uses information about patent citations to track and discuss the evolution of knowledge flows to a set of selected countries involved in catching-up up processes.. The analysis comprises an analysis of patent citation data extracted from the USPTO database from the period 1982-2006, including information about citations extracted from patents granted by national companies of the selected countries, presented trough technological interaction matrices crossing information of different technological domains of the patents, correlating the technological domains of the patents citing other patents with the technological domains of the patents cited. The hypothesis is that the intensification and diversification of knowledge flows to a gr...

2012

Since Schumpeter's seminal work on economic development (Schumpeter 1934), innovation is considered as one of the main drivers of firm performance and economic growth. At the same time, technological innovations vary considerably in terms of impact with only a minority of new inventions contributing significantly to economic growth. More recently a number of indicators derived from patent documents have been advanced to capture the nature and impact of technological inventions. Within this paper, we compare and validate these indicators within the field of biotechnology. An extensive analysis of the recent history of biotechnology allows us to identify the most important inventions (n=308) that shaped the field of biotechnology for the time period 1976-2001. A considerable number of these inventions have been patented between 1976 and 2001 (n= 215; 70%). For all USPTO biotech patents filed between 1976 and 2001 (n= 84,119) relevant indicators have been calculated. Within a next step, we assess which indicators allow to distinguish between most important patented inventions and their less influential counterparts by means of logistic regression models. Our findings reveal that the use of multiple, complementary, indicators provides the most comprehensive picture. In addition, it becomes clear that ex post indicators reflecting impact and value outperform ex ante indicators reflecting the nature and novelty of the invention in terms of precision and recall.

CIRCLE Electronic Working Papers, 2007

Electricity has been regarded as a typical example of a general purpose technology and important for the surge both in energy productivity and overall productivity in the American economy in the 1920s. This view was challenged by Nicholas and Moser based on patent statistics. We argue that other methods are required for studying productivity effects and propose cointegration analyses. We demonstrate a clear impact from electrification on energy productivity in those broad Swedish industrial branches that used electricity for multiple uses. This effect goes beyond mere book-keeping effects and indicates the existence of dynamic effects.

UNIVERSITY OF MALAYA, 2006

This paper identifies the causal impact of the U.S. rural electrification on agricultural innovation between 1910 and 1950. We combine cross-county variation in access to the closest hydro-power plant and cross-crop variation in energy use before the arrival of electricity to identify the effect of electrification on the number of electric patents related to each of these crops. We find evidence that agricultural innovation responded to local incentives, and thus having access to cheaper electricity increases the number of electric patents-specially for energy-intensive crops, while total patents did not respond. This would be consistent with theories of endogenous technological change where inventions respond to local relative factor prices and market size is not a factor because agricultural products are commodities. As further indication of this, we find larger impacts in counties with labour shortages, whilst there are no such differences seen in counties with larger market sizes. 0 I am especially grateful to my supervisor, Prof. Jeanne Lafortune, for the dedicated support, guidance, encouragement and advice she has provided throughout this project. Thanks also to Carl Kitchens and Price Fishback for kindly sharing their data. I wish to extend my thanks to Jakob Schneebacher and Felipe González for the valuable comments provided. The views presented in this paper are my own and do not necessarily reflect those of

This Article reports an empirical study of the network composed of patent “nodes” and citation “links” between them. It builds on an earlier study in which we argued that trends in the growth of the patent citation network provide evidence that the explosive growth in patenting in the late twentieth century was due at least in part to the issuance of increasingly trivial patents. We defined a measure of patent stratification based on comparative probability of citation; an increase in this measure suggests that the USPTO is issuing patents of comparatively less technological significance. Provocatively, we found that stratification increased in the 1990s during the “patent explosion.” Here we report a further study indicating that the trend toward increasing stratification leveled off beginning around 2000. This observation suggests that there was a de facto tightening of patentability standards well before the doctrinal shifts reflected in the Supreme Court’s flurry of patent activ...

The Economic Journal, 2003

This is an important book that will influence future research on R&D and innovation. It brings together a number of pioneering papers by Adam Jaffe and Manuel Trajtenberg (and various co-authors) on the use of patent citations to study the innovation process, plus several new pieces of work. The book is organised in four parts. The papers in Part 1 lay the 'conceptual' groundwork for research on patent citations. The first is the classic paper by Trajtenberg demonstrating that citations are linked to demand-based measures of social surplus for one important medical innovation, CT scanners. Making this link between patent citations and social (and private) value provides powerful justification for using citations in economic studies. It is surprising and unfortunate that there have not been similar studies on other innovations, despite the huge growth of empirical work on vertically differentiated product markets.