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A Model of Research, Patenting, and Technological Change


  • Samuel Kortum


I use the aggregate behavior of three indicators of technology (employment of research scientists and engineers, patented inventions, and total factor productivity) to identify a plausible model of endogenous technological change. In the US (as well as in other developed countries) research employment and total factor productivity have both grown, while the rate of patenting has remained relatively flat. One interpretation of these facts is that: (i) patentable inventions are becoming increasingly difficult to discover as the quality of techniques in use increases, (ii) inventions which are patented represent percentage improvements on techniques currently in use, and (iii) the size of the economy is growing, making patents increasingly valuable and justifying increased research efforts devoted to discovering them. This paper presents a general equilibrium search theoretic model of invention which formalizes this view.

Suggested Citation

  • Samuel Kortum, 1994. "A Model of Research, Patenting, and Technological Change," NBER Working Papers 4646, National Bureau of Economic Research, Inc.
  • Handle: RePEc:nbr:nberwo:4646
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    References listed on IDEAS

    1. Aghion, Philippe & Howitt, Peter, 1992. "A Model of Growth through Creative Destruction," Econometrica, Econometric Society, vol. 60(2), pages 323-351, March.
    2. Charles I. Jones, 1995. "Time Series Tests of Endogenous Growth Models," The Quarterly Journal of Economics, Oxford University Press, vol. 110(2), pages 495-525.
    3. repec:fth:harver:1473 is not listed on IDEAS
    4. Zvi Griliches, 1998. "Patent Statistics as Economic Indicators: A Survey," NBER Chapters,in: R&D and Productivity: The Econometric Evidence, pages 287-343 National Bureau of Economic Research, Inc.
    5. Ricardo J. Caballero & Adam B. Jaffe, 1993. "How High are the Giants' Shoulders: An Empirical Assessment of Knowledge Spillovers and Creative Destruction in a Model of Economic Growth," NBER Chapters,in: NBER Macroeconomics Annual 1993, Volume 8, pages 15-86 National Bureau of Economic Research, Inc.
    6. Pakes, Ariel S, 1986. "Patents as Options: Some Estimates of the Value of Holding European Patent Stocks," Econometrica, Econometric Society, vol. 54(4), pages 755-784, July.
    7. Edwin Mansfield, 1986. "Patents and Innovation: An Empirical Study," Management Science, INFORMS, vol. 32(2), pages 173-181, February.
    8. Jean Olson Lanjouw, 1993. "Patent Protection: Of What Value and for How Long?," NBER Working Papers 4475, National Bureau of Economic Research, Inc.
    9. Mansfield, Edwin & Schwartz, Mark & Wagner, Samuel, 1981. "Imitation Costs and Patents: An Empirical Study," Economic Journal, Royal Economic Society, vol. 91(364), pages 907-918, December.
    10. Cockburn, Iain & Henderson, Rebecca, 1994. "Racing to Invest? The Dynamics of Competition in Ethical Drug Discovery," Journal of Economics & Management Strategy, Wiley Blackwell, vol. 3(3), pages 481-519, Fall.
    11. Kortum, S., 1991. "R & D Patents and the Progress of Technology in a Search Model," Papers 17, Boston University - Department of Economics.
    12. Oulton,Nicholas & O'Mahony,Mary, 1994. "Productivity and Growth," Cambridge Books, Cambridge University Press, number 9780521453455, May.
    13. Robert Evenson, 1984. "International Invention: Implications for Technology Market Analysis," NBER Chapters,in: R&D, Patents, and Productivity, pages 89-126 National Bureau of Economic Research, Inc.
    14. Evenson, Robert E & Kislev, Yoav, 1976. "A Stochastic Model of Applied Research," Journal of Political Economy, University of Chicago Press, vol. 84(2), pages 265-281, April.
    15. Reinganum, Jennifer F., 1989. "The timing of innovation: Research, development, and diffusion," Handbook of Industrial Organization,in: R. Schmalensee & R. Willig (ed.), Handbook of Industrial Organization, edition 1, volume 1, chapter 14, pages 849-908 Elsevier.
    16. Richard C. Levin & Alvin K. Klevorick & Richard R. Nelson & Sidney G. Winter, 1987. "Appropriating the Returns from Industrial Research and Development," Brookings Papers on Economic Activity, Economic Studies Program, The Brookings Institution, vol. 18(3, Specia), pages 783-832.
    17. Judd, Kenneth L, 1985. "On the Performance of Patents," Econometrica, Econometric Society, vol. 53(3), pages 567-585, May.
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    Cited by:

    1. Carmelo Pierpaolo Parello, 2009. "Information Gathering, Innovation and Growth," Working Papers 122, University of Rome La Sapienza, Department of Public Economics.

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