Manuel Trajtenberg

A Penny for Your Quotes : Patent Citations and the Value of Innovations

The use of patents in economic research has been seriously hindered by the fact that patents vary enormously in their importance or value, and hence, simple patent counts cannot be informative about innovative output. The purpose of this article is to put forward patent counts weighted by citations as indicators of the value of innovations, thereby overcoming the limitations of simple counts. The empirical analysis of a particular innovation (Computed Tomography scanners) indeed shows a close association between citation-based patent indices and independent measures of the social value of innovations in that field. Moreover, the weighting scheme appears to be nonlinear (increasing) in the number of citations, implying that the informational content of citations rises at the margin. As in previous studies, simple patent counts are found to be highly correlated with contemporaneous RD however, here the association is within a field over time rather than cross-sectional.

The Names Game: Harnessing Inventors, Patent Data for Economic Research

The goal of this paper is to lay out a methodology and corresponding computer algorithms, that allow us to extract the detailed data on inventors contained in patents, and harness it for economic research. Patent data has long been used in empirical research in economics, and yet the information on the identity (i.e. the names and location) of the patents’ inventors has seldom been deployed in a large scale, primarily because of the “who is who” problem: the name of a given inventor may be spelled differently across her/his patents, and the exact same name may correspond to different inventors (i.e. the “John Smith” problem). Given that there are over 2 million patents with 2 inventors per patent on average, the “who is who” problem applies to over 4 million “records”, which is obviously too large to tackle manually. We have thus developed an elaborate methodology and computerized procedure to address this problem in a comprehensive way. The end result is a list of 1.6 million unique inventors from all over the world, with detailed data on their patenting histories, their employers, co-inventors, etc. Forty percent of them have more than one patent, and 70,000 have more than 10 patents. We can trace those multiple inventors across time and space, and thus study the causes and consequences of their mobility across countries, regions, and employers. Given the increasing availability of large computerized data sets on individuals, there may be plenty of opportunities to deploy this methodology to other areas of economic research as well.

A General-Purpose Technology at Work: The Corliss Steam Engine in the Late- Nineteenth-Century United States

The contribution to growth from the steam engine—Industrial Revolution icon and prime example of a “General Purpose Technology”—has remained unclear. This article examines the role that a particular design improvement in steam power, embodied in the Corliss engine, played in the growth of the U.S. economy in the late nineteenth century. Using detailed data on the location of Corliss engines and waterwheels and a two-stage estimation strategy, we show that the deployment of Corliss engines served as a catalyst for the industrys massive relocation into large urban centers, thus fueling agglomeration economies and further population growth.

Innovation Policy for Development: an Overview

This paper was prepared for the LAEBA 2005 second annual meeting in Buenos Aires, Argentina. It is meant to provide a framework for thinking systematically about innovation policies for development, without venturing into specific, recipe-like policy recommendations. It does so by identifying and dissecting the key issues that arise in this context, and by examining in some detail the case of innovation policy in Israel, which sheds light both on the promise and the limitations of such policies.

R&D Policy in Israel

The high tech sector in Israel has turned in the course of the last decade into a striking economic success story, both by local and by international standards. In fact, Israel stands as one of the most prolific innovating economies, and as one of the few Silicon Valley types of technology centers in the world. There is no doubt that government policy was key to the emergence and early success of the sector, a policy embedded for the most part in the programs and budgetary resources of the Office of the Chief Scientist (OCS) at the Ministry of Industry and Trade. However, the very success of the sector and its relentless dynamism call for the periodic revision and reexamination of those policies. Moreover, the policy impasse of the late 1990s (due to tight government funding at a time of growing demand for Research and Development (R&D) funding) brought to the surface basic tensions that were built into the policies, and that could no longer be ignored.

The use of multivariate regression analysis in contrast-detail studies of CT scanners.

Previous studies of the imaging performance of computed tomography (CT) scanners, and other imaging modalities, have failed to apply appropriate statistical methods to data analysis, thus impairing the accuracy and significance of results. Given that imaging performance involves a number of interrelated variables and an element of randomness, its empirical assessment requires multivariate regression analysis. This method is used here to analyze anew a set of contrast-detail data from a previous study on CT scanners. The main issues considered are the specification of the proper functional form linking perceptibility, dose and contrast, the estimation of the contrast and dose coefficients, and of scanner-specific constants to be used in computing indices of imaging quality. One of the main empirical findings is that the dose coefficient of the CT scanners studied is significantly less than that predicted by the theoretical model: 1/5 instead of 1/3. This result suggests that actual dose used in routine clinical studies could be reduced substantially without impairing much the quality of the images. On the other hand, the coefficient of contrast does correspond to its predicted value, i.e., 2/3. The methodology used here is not limited to the contrast-detail framework, but is applicable to, and indeed essential in, empirical studies of the performance of any imaging modality.

Together but Apart: ICT and Productivity Growth in Israel

There is widespread agreement about the important role played by Information and Communication Technologies (ICTs) in the US productivity revival and in the evolving US-EU productivity gap. In Israel, the ICT sector grew very rapidly during the 1990s and became a hotbed of innovation and technological advance by worldwide standards. Yet, Israels overall productivity growth remained sluggish, with traditional sectors both in manufacturing and services seemingly unable to benefit from the success of the ICT sector. The main goal of this paper is to shed light on these twin developments. We use newly constructed data on industry-level ICT investments between 1990 and 2003 and estimate production functions for manufacturing industries augmented to include ICT capital. We find a significant elasticity of value-added with respect to ICT capital, which increases considerably with the technological sophistication of the industry. We also find that ICT capital deepening is the most important factor contributing to value added growth in manufacturing during 1995-2000, before the burst of the dot.com bubble. Because most ICT capital is concentrated in high tech industries, growth in manufacturing has been mostly confined to the high-tech sector. Facilitating the adoption of ICT in traditional industries is therefore crucial to achieving economy-wide growth. The Israeli experience described here - although restricted to the manufacturing sector - provides a useful example of the benefits and limitations associated with a growth strategy centred on a local ICT producing sector, however successful it might be.