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The NBER Patent Citations Data File: Lessons, Insights and Methodological Tools


  • Hall, Bronwyn H
  • Jaffe, Adam B
  • Trajtenberg, Manuel


This Paper describes the database on US patents that we have developed over the past decade, with the goal of making it widely accessible for research. We present main trends in US patenting over the last 30 years, including a variety of original measures constructed with citation data, such as backward and forward citation lags, indices of ‘originality’ and ‘generality’, self-citations, etc. Many of these measures exhibit interesting differences across the six main technological categories that we have developed (comprising Computers and Communications, Drugs and Medical, Electrical and Electronics, Chemical, Mechanical and Others), differences that call for further research. To stimulate such research, the entire database — about 3 million patents and 16 million citations — is now available on the NBER website. We discuss key issues that arise in the use of patent citations data, and suggest ways of addressing them. In particular, significant changes over time in the rate of patenting and in the number of citations made, as well as the inevitable truncation of the data, make it very hard to use the raw number of citations received by different patents directly in a meaningful way. To remedy this problem we suggest two alternative approaches: the fixed-effects approach involves scaling citations by the average citation count for a group of patents to which the patent of interest belongs; the quasi-structural approach attempts to distinguish the multiple effects on citation rates via econometric estimation.

Suggested Citation

  • Hall, Bronwyn H & Jaffe, Adam B & Trajtenberg, Manuel, 2001. "The NBER Patent Citations Data File: Lessons, Insights and Methodological Tools," CEPR Discussion Papers 3094, C.E.P.R. Discussion Papers.
  • Handle: RePEc:cpr:ceprdp:3094

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    References listed on IDEAS

    1. Bresnahan, Timothy F. & Trajtenberg, M., 1995. "General purpose technologies 'Engines of growth'?," Journal of Econometrics, Elsevier, vol. 65(1), pages 83-108, January.
    2. Adam Jaffe & Manuel Trajtenberg, 1999. "International Knowledge Flows: Evidence From Patent Citations," Economics of Innovation and New Technology, Taylor & Francis Journals, vol. 8(1-2), pages 105-136.
    3. 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.
    4. Jean O. Lanjouw & Mark Schankerman, 1999. "The Quality of Ideas: Measuring Innovation with Multiple Indicators," NBER Working Papers 7345, National Bureau of Economic Research, Inc.
    5. Adam B. Jaffe & Manuel Trajtenberg & Rebecca Henderson, 1993. "Geographic Localization of Knowledge Spillovers as Evidenced by Patent Citations," The Quarterly Journal of Economics, Oxford University Press, vol. 108(3), pages 577-598.
    6. Scherer, F M, 1982. "Inter-Industry Technology Flows and Productivity Growth," The Review of Economics and Statistics, MIT Press, vol. 64(4), pages 627-634, November.
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    More about this item


    citations; data construction; patents; truncation;

    JEL classification:

    • O30 - Economic Development, Innovation, Technological Change, and Growth - - Innovation; Research and Development; Technological Change; Intellectual Property Rights - - - General


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