Close to you? Bias and precision in patent-based measures of technological proximity
Patent data have been widely used in research to characterize firms' locations in technological or knowledge space, as well as the proximities among firms. Researchers have measured firms' technological or knowledge proximities with a variety of measures based on patent data, including Euclidean distances (using the technological classifications listed on patents), and overlap in cited patents. Often research has employed only the first listed patent classification in measures of proximities. We explore the effects of using the first listed patent class as well as other methods to measure proximities. We point out that measures of proximity based on small numbers of patents are imprecisely measured random variables. Measures computed on samples with few patents or a single patent class generate both biased and imprecise measures of proximity. We discuss the implications of this for typical research questions employing measures of proximity, and explore the effects of larger sample sizes and coarser patent class breakdowns in mitigating these problems. Where possible, we suggest that researchers increase their sample sizes by aggregating years or using all of the listed patent classes on a patent, rather than just the first.
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- Hall, B. & Jaffe, A. & Trajtenberg, M., 2001.
"The NBER Patent Citations Data File: Lessons, Insights and Methodological Tools,"
2001-29, Tel Aviv.
- 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.
- Bronwyn H. Hall & Adam B. Jaffe & Manuel Trajtenberg, 2001. "The NBER Patent Citation Data File: Lessons, Insights and Methodological Tools," NBER Working Papers 8498, National Bureau of Economic Research, Inc.
- Lori Rosenkopf & Paul Almeida, 2003. "Overcoming Local Search Through Alliances and Mobility," Management Science, INFORMS, vol. 49(6), pages 751-766, June.
- Juan Alcácer & Michelle Gittelman, 2006. "Patent Citations as a Measure of Knowledge Flows: The Influence of Examiner Citations," The Review of Economics and Statistics, MIT Press, vol. 88(4), pages 774-779, November.
- Brian S. Silverman, 1999. "Technological Resources and the Direction of Corporate Diversification: Toward an Integration of the Resource-Based View and Transaction Cost Economics," Management Science, INFORMS, vol. 45(8), pages 1109-1124, August.
- Adam B. Jaffe & Manuel Trajtenberg & Rebecca Henderson, 1992.
"Geographic Localization of Knowledge Spillovers as Evidenced by Patent Citations,"
NBER Working Papers
3993, National Bureau of Economic Research, Inc.
- 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.
- Jaffe, A.B. & Trajtenberg, M., 1992. "Geographic Localization of Knowledge Spillovers as Evidenced by Patent Citations," Papers 14-92, Tel Aviv.
- Manuel Trajtenberg & Adam B. Jaffe & Michael S. Fogarty, 2000. "Knowledge Spillovers and Patent Citations: Evidence from a Survey of Inventors," American Economic Review, American Economic Association, vol. 90(2), pages 215-218, May.
- Lucia Piscitello, 2004. "Corporate diversification, coherence and economic performance," Industrial and Corporate Change, Oxford University Press, vol. 13(5), pages 757-787, October.
- Jaeyong Song & Paul Almeida & Geraldine Wu, 2003. "Learning--by--Hiring: When Is Mobility More Likely to Facilitate Interfirm Knowledge Transfer?," Management Science, INFORMS, vol. 49(4), pages 351-365, April.
- Constance E. Helfat, 1994. "Evolutionary Trajectories in Petroleum Firm R&D," Management Science, INFORMS, vol. 40(12), pages 1720-1747, December.
- Fleming, Lee & Sorenson, Olav, 2001. "Technology as a complex adaptive system: evidence from patent data," Research Policy, Elsevier, vol. 30(7), pages 1019-1039, August.
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