Patents, Citations, and Innovations

Patents, Citations, and Innovations

A Window on the Knowledge Economy

By Manuel Trajtenberg and Adam B. Jaffe

Foreword by Paul M. Romer





Innovation and technological change, long recognized as the main drivers of long-term economic growth, are elusive notions that are difficult to conceptualize and even harder to measure in a consistent, systematic way. This book demonstrates the usefulness of patents and citations data as a window on the process of technological change and as a powerful tool for research on the economics of innovation. Patent records contain a wealth of information, including the inventors' identity, location, and employer, as well as the technological field of the invention. Patents also contain citation references to previous patents, which allow one to trace links across inventions.

The book lays out the conceptual foundations for such research and provides a range of interesting applications, such as examining the geographic pattern of knowledge spillovers and evaluating the impact of university and government patenting. It also describes statistical tools designed to handle methodological problems raised by the patent and citation processes. The book is accompanied by a set of auxiliary materials, including complete data on 3 million patents with more than 16 million citations and a range of author-devised measures of the importance, generality, and originality of patented innovations. This is available for download at


Out of Print ISBN: 9780262100953 496 pp. | 6 in x 9 in 96 illus.


$45.00 X ISBN: 9780262600651 496 pp. | 6 in x 9 in 96 illus.


Paul M. Romer.


  • A useful book full of careful measurement of the incentives, institutions, and causal flows in the knowledge economy. Shows both the importance of the knowledge economy (now denied by fools on Wall Street) and how sound economic analysis applies to it (recently denied by the same fools.)

    Timothy F. Bresnahan

    Professor of Economics, Stanford University

  • Knowledge, which is hard to measure, is the core of modern economic growth. Jaffe and Trajtenberg have assembled the most comprehensive data set on patent citations, which allows them to trace major channels of knowledge creation. This outstanding book, which describes these data and puts them to good use, is a landmark in research on innovation and economic growth.

    Elhanan Helpman

    Department of Economics, Harvard University, and The Eitan Berglas School of Economics, Tel Aviv University

  • Since the time of Galileo, Kepler, and Francis Bacon, it has been recognized that scientific knowledge advances through careful measurement. Determining how scientific knowledge affects economic well-being has been a tougher nut to crack. This volume collects pioneering essays on the use of citations data to measure knowledge flows among scientists and engineers and the impact of those flows on economic growth.

    F. M. Scherer

    Professor Emeritus, John F. Kennedy School of Government, Harvard University

  • Jaffe, Trajtenberg, and their several co-authors have provided compelling evidence that patent data, combined with citation analysis, can be made to provide powerful insights into the performance of the knowledge economy. This book is, quite simply, required reading for anyone seeking empirical evidence relating to the determinants of economic growth.

    Nathan Rosenberg

    Professor of Economics (Emeritus), Stanford University

  • The studies here represent the best recent research using patents to measure inventive activity. The availability of this volume will inspire and assist future research on this important subject.

    Martin Feldstein

    President, National Bureau of Economic Research, and Professor of Economics, Harvard University

  • This book is both a major contribution to our understanding of the economic impact of the inventive and innovative activities that underlie economic progress and structural change, and a fitting tribute to the late Zvi Griliches by economists whom he trained. It reports on research based heavily on recent progress in computerizing data on science and technology, and should be read by scholars from all disciplines and all countries who share this endeavor.

    Keith Pavitt

    R. M. Phillips Professor of Science and Technology Policy, University of Sussex, England

  • Jaffe and Trajtenberg's use of the citation information on patent documents to indicate who gains from the knowledge creation of others, is a true breakthrough in an important measurement problem. It enables a scientific study of the causes and effects of research activity, and the numerous policy issues associated with the research and innovation process. This book both shows how to use this new data, and provides a diskette which enables us all to incorporate that data in our own future research.

    Ariel Pakes

    Professor of Economics, Harvard University