The size distribution of innovations revisited: An application of extreme value statistics to citation and value measures of patent significance
This paper focuses on the analysis of size distributions of innovations, which are known to be highly skewed. We use patent citations as one indicator of innovation significance, constructing two large datasets from the European and US Patent Offices at a high level of aggregation, and the Trajtenberg (1990) dataset on CT scanners at a very low one. We also study self-assessed reports of patented innovation values using two very recent patent valuation datasets from the Netherlands and the UK, as well as a small dataset of patent license revenues of Harvard University. Statistical methods are applied to analyse the properties of the empirical size distributions, where we put special emphasis on testing for the existence of ‘heavy tails’, i.e., whether or not the probability of very large innovations declines more slowly than exponentially. While overall the distributions appear to resemble a lognormal, we argue that the tails are indeed fat. We invoke some recent results from extreme value statistics and apply the Hill (1975) estimator with data-driven cut-offs to determine the tail index for the right tails of all datasets except the NL and UK patent valuations. On these latter datasets we use a maximum likelihood estimator for grouped data to estimate the Pareto exponent for varying definitions of the right tail. We find significantly and consistently lower tail estimates for the returns data than the citation data (around 0.7 vs. 3-5). The EPO and US patent citation tail indices are roughly constant over time (although the US one does grow somewhat in the last periods) but the latter estimates are significantly lower than the former. The heaviness of the tails, particularly as measured by financial indices, we argue, has significant implications for technology policy and growth theory, since the second and possibly even the first moments of these distributions may not exist. (JEL Codes: C16, O31, O33 Keywords: returns to invention, patent citations, extreme-value
(This abstract was borrowed from another version of this item.)
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Drees, Holger & Kaufmann, Edgar, 1998. "Selecting the optimal sample fraction in univariate extreme value estimation," Stochastic Processes and their Applications, Elsevier, vol. 75(2), pages 149-172, July.
- Gerald Silverberg & Bart Verspagen, 2002.
"A Percolation Model of Innovation in Complex Technology Spaces,"
Computing in Economics and Finance 2002
24, Society for Computational Economics.
- Silverberg, Gerald & Verspagen, Bart, 2005. "A percolation model of innovation in complex technology spaces," Journal of Economic Dynamics and Control, Elsevier, vol. 29(1-2), pages 225-244, January.
- Silverberg, G. & Verspagen, B., 2002. "A Percolation Model of Innovation in Complex Technology Spaces," Working Papers 02.12, Eindhoven Center for Innovation Studies.
- Adam B. Jaffe & Manuel Trajtenberg & Michael S. Fogarty, 2000. "The Meaning of Patent Citations: Report on the NBER/Case-Western Reserve Survey of Patentees," NBER Working Papers 7631, National Bureau of Economic Research, Inc.
- Bronwyn H. Hall & Adam Jaffe & Manuel Trajtenberg, 2001.
"Market Value and Patent Citations: A First Look,"
Development and Comp Systems
- Hall, Bronwyn H. & Jaffee, Adam & Trajtenberg, Manuel, 2000. "Market Value and Patent Citations: A First Look," Department of Economics, Working Paper Series qt1rh8k6z2, Department of Economics, Institute for Business and Economic Research, UC Berkeley.
- Bronwyn H. Hall & Adam Jaffe & Manuel Trajtenberg, 2002. "Market Value and Patent Citations: A First Look," Development and Comp Systems 0201001, EconWPA.
- Bronwyn H. Hall, Adam Jaffe and Manuel Trajtenberg., 2000. "Market Value and Patent Citations: A First Look," Economics Working Papers E00-277, University of California at Berkeley.
- Bronwyn Hall & Adam Jaffe & Manuel Trajenberg, 2000. "Market Value and Patent Citations: A First Look," Economics Series Working Papers 2000-W17, University of Oxford, Department of Economics.
- Bronwyn H. Hall & Adam B. Jaffe & Manuel Trajtenberg, 2000. "Market Value and Patent Citations: A First Look," NBER Working Papers 7741, National Bureau of Economic Research, Inc.
- Bronwyn H. Hall and Adam Jaffe, and Manuel Trajtenberg., 2001. "Market Value and Patent Citations: A First Look," Economics Working Papers E01-304, University of California at Berkeley.
- Hall, Bronwyn H. & Jaffe, Adam & Trajtenberg, Manuel, 2001. "Market Value and Patent Citations: A First Look," Department of Economics, Working Paper Series qt8vh1c20f, Department of Economics, Institute for Business and Economic Research, UC Berkeley.
- repec:adr:anecst:y:1998:i:49-50:p:19 is not listed on IDEAS
- Yannis KATSOULACOS & David ULPH, 1998. "Innovation Spillovers and Technology Policy," Annals of Economics and Statistics, GENES, issue 49-50.
- Dietmar Harhoff & Francis Narin & F. M. Scherer & Katrin Vopel, 1999. "Citation Frequency And The Value Of Patented Inventions," The Review of Economics and Statistics, MIT Press, vol. 81(3), pages 511-515, August.
- De Vany, Arthur S. & Walls, W. David, 2004. "Motion picture profit, the stable Paretian hypothesis, and the curse of the superstar," Journal of Economic Dynamics and Control, Elsevier, vol. 28(6), pages 1035-1057, March.
- Lux, T., .
"The Limiting Extremal Behaviour of Speculative Returns: An Analysis of Intra-Daily Data from the Frankfurt Stock Exchange,"
Discussion Paper Serie B
436, University of Bonn, Germany, revised Jul 1998.
- Thomas Lux, 2001. "The limiting extremal behaviour of speculative returns: an analysis of intra-daily data from the Frankfurt Stock Exchange," Applied Financial Economics, Taylor & Francis Journals, vol. 11(3), pages 299-315.
- Hall, Peter, 1990. "Using the bootstrap to estimate mean squared error and select smoothing parameter in nonparametric problems," Journal of Multivariate Analysis, Elsevier, vol. 32(2), pages 177-203, February.
- Simon Kuznets, 1962. "Inventive Activity: Problems of Definition and Measurement," NBER Chapters, in: The Rate and Direction of Inventive Activity: Economic and Social Factors, pages 19-52 National Bureau of Economic Research, Inc.
- Manuel Trajtenberg, 1990. "A Penny for Your Quotes: Patent Citations and the Value of Innovations," RAND Journal of Economics, The RAND Corporation, vol. 21(1), pages 172-187, Spring.
- Scherer, F. M. & Harhoff, Dietmar, 2000. "Technology policy for a world of skew-distributed outcomes," Research Policy, Elsevier, vol. 29(4-5), pages 559-566, April.
- Silverberg, G. & Verspagen, B., 2003. "Brewing the future: stylized facts about innovation and their confrontation with a percolation model," Working Papers 03.06, Eindhoven Center for Innovation Studies.
When requesting a correction, please mention this item's handle: RePEc:eee:econom:v:139:y:2007:i:2:p:318-339. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Zhang, Lei)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.