TY  - JOUR
AU  - Jaffe,Adam B.
AU  - Trajtenberg,Manuel
AU  - Henderson,Rebecca
TI  - Geographic Localization of Knowledge Spillovers as Evidenced by Patent  Citations
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 3993
PY  - 1992
Y2  - February 1992
UR  - http://www.nber.org/papers/w3993
L1  - http://www.nber.org/papers/w3993.pdf
N1  - Author contact info:
Adam B. Jaffe
PO Box 24390
Wellington 6142
New Zealand
Tel: 64-4-939-4250
E-Mail: adam.jaffe@motu.org.nz

Manuel Trajtenberg
Eitan Berglas School of Economics
Tel-Aviv University
Tel-Aviv 69978
ISRAEL
Tel: 972-3-640-9911
Fax: 972-3-640-9908
E-Mail: manuel@post.tau.ac.il

Rebecca Henderson
Heinz Professor of Environmental Management
Harvard Business School
Morgan 445
Soldiers Field
Boston, MA 02163
Tel: 617/495-8014
Fax: 617/496-4072
E-Mail: rhenderson@hbs.edu
AB  - We compare the geographic location of patent citations to those of the cited patents, as evidence of the extent to which knowledge spillovers are geographically localized. We find that citations to U.S. patents are more likely to come from the U.S., and more likely to come from the same state and SMSA as the cited patents than one would expect based only on the preexisting concentration of related research activity. These effects are particularly significant at the local (SMSA) level, and are particularly apparent in early citations.
ER  -