TY  - JOUR
AU  - Azoulay, Pierre
AU  - Zivin, Joshua S. Graff
AU  - Sampat, Bhaven N
TI  - The Diffusion of Scientific Knowledge Across Time and Space: Evidence from Professional Transitions for the Superstars of Medicine
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 16683
PY  - 2011
Y2  - January 2011
DO  - 10.3386/w16683
UR  - http://www.nber.org/papers/w16683
L1  - http://www.nber.org/papers/w16683.pdf
N1  - Author contact info:
Pierre Azoulay
MIT Sloan School of Management
100 Main Street, E62-487
Cambridge, MA 02142
Tel: 617/258-9766
Fax: 617/253-2660
E-Mail: pazoulay@mit.edu

Joshua S. Graff Zivin
University of California, San Diego
9500 Gilman Drive, MC 0519
La Jolla, CA 92093-0519
Tel: 858/822-6438
E-Mail: jgraffzivin@ucsd.edu

Bhaven N. Sampat
Department of Health Policy and Management
Columbia University
722 W 168th Street, Room 486
New York, NY 10032
Tel: 212/305-7293
E-Mail: bns3@columbia.edu
M1  - published as Pierre Azoulay, Joshua S. Graff Zivin, Bhaven N. Sampat. "The Diffusion of Scientific Knowledge across Time and Space: Evidence from Professional Transitions for the Superstars of Medicine," in Josh Lerner and Scott Stern, editors, "The Rate and Direction of Inventive Activity Revisited" University of Chicago Press (2012)

AB  - Are scientific knowledge flows embodied in individuals, or "in the air"? To answer this question, we measure the effect of labor mobility in a sample of 9,483 elite academic life scientists on the citation trajectories associated with individual articles (resp. patents) published (resp. granted) before the scientist moved to a new institution. We find that article-to-article citations from the scientific community at the superstar's origin location are barely affected by their departure. In contrast, article-to-patent citations, and especially patent-to-patent citations, decline at the origin location following a star's departure, suggesting that spillovers from academia to industry are not completely disembodied. We also find that article-to-article citations at the superstar's destination location markedly increase after they move. Our results suggest that, to be realized, knowledge flows to industry may require more face-to-face interaction than those to academics. Moreover, to the extent that academic scientists do not internalize the effect of their location decisions on the circulation of ideas, our results raise the intriguing possibility that barriers to labor mobility in academic science limit the recombination of individual bits of knowledge, resulting in a suboptimal rate of scientific exploration.
ER  -