The Quality of Ideas: Measuring Innovation with Multiple Indicators
We model early expectations about the value and technological importance ('quality') of a patented innovation as a latent variable common to a set of four indicators: the number of patent claims, forward citations, backward citations and family size. The model is estimated for four technology areas using a sample of about 8000 U.S. patents applied for during 1960-91. We measure how much noise' each individual indicator contains and construct a more informative, composite measure of quality. The variance in quality', conditional on the four indicators, is just one-third of the unconditional variance. We show the variance reduction generated by subsets of indicators, and find forward citations to be particularly important. Our measure of quality is significantly related to subsequent decisions to renew a patent and to litigate infringements. Using patent and R&D data for 100 U.S. manufacturing firms, we find that adjusting for quality removes much of the apparent decline in research productivity (patent counts per R&D) observed at the aggregate level.
|Date of creation:||Sep 1999|
|Publication status:||published as Lanjouw, Jean O. and Mark Schankerman. "Patent Quality And Research Productivity: Measuring Innovation With Multiple Indicators," Economic Journal, 2004, v114(495,Apr), 441-465.|
|Contact details of provider:|| Postal: National Bureau of Economic Research, 1050 Massachusetts Avenue Cambridge, MA 02138, U.S.A.|
Web page: http://www.nber.org
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- Zvi Griliches, 1998.
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NBER Chapters,in: R&D and Productivity: The Econometric Evidence, pages 287-343
National Bureau of Economic Research, Inc.
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- Jean Olson Lanjouw, 1998. "Patent Protection in the Shadow of Infringement: Simulation Estimations of Patent Value," Review of Economic Studies, Oxford University Press, vol. 65(4), pages 671-710.
- Pakes, Ariel & Schankerman, Mark A., 1978. "The Rate of Obsolescence of Knowledge, Research Gestation Labs, and the Private Rate of Return to Research Resources," Working Papers 78-13, C.V. Starr Center for Applied Economics, New York University.
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- Mark Schankerman, 1998. "How Valuable is Patent Protection? Estimates by Technology Field," RAND Journal of Economics, The RAND Corporation, vol. 29(1), pages 77-107, Spring.
- Ariel Pakes & Mark Schankerman, 1984. "The Rate of Obsolescence of Patents, Research Gestation Lags, and the Private Rate of Return to Research Resources," NBER Chapters,in: R&D, Patents, and Productivity, pages 73-88 National Bureau of Economic Research, Inc. Full references (including those not matched with items on IDEAS)
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