Identifying the age profile of patent citations: new estimates of knowledge diffusion

Aditi Mehta, Marc Rysman and Tim Simcoe

Journal of Applied Econometrics, 2010, vol. 25, issue 7, 1179-1204

Abstract: Previous research studies the age profile of patent citations to learn about knowledge flows over time. However, identification is problematic because of the collinearity between application year, citation year, and patent age. We show empirically that a patent's ‘citation clock’ does not start until it issues, and propose a highly flexible identification strategy that uses the lag between application and grant as a source of exogenous variation. We examine the potential bias if our assumptions are incorrect, and discuss extensions into other research areas. Finally, we use our method to re-examine prior results on citation age profiles of patents from different technological fields and application year cohorts. Copyright (C) 2009 John Wiley & Sons, Ltd.

Date: 2010
References: Add references at CitEc
Citations: View citations in EconPapers (43)

Downloads: (external link)
http://hdl.handle.net/10.1002/jae.1086

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:jae:japmet:v:25:y:2010:i:7:p:1179-1204

Ordering information: This journal article can be ordered from
http://www3.intersci ... e.jsp?issn=0883-7252

Access Statistics for this article

Journal of Applied Econometrics is currently edited by M. Hashem Pesaran

More articles in Journal of Applied Econometrics from John Wiley & Sons, Ltd.
Bibliographic data for series maintained by Wiley-Blackwell Digital Licensing () and Christopher F. Baum ().