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Patent Citations - An Analysis of Quality Differences and Citing Practices in Hybrid Corn

52 Pages Posted: 18 Jul 2011 Last revised: 14 Mar 2016

Petra Moser

Leonard N. Stern School of Business - Department of Economics; National Bureau of Economic Research (NBER)

Joerg Ohmstedt

Bain & Company; Cornell University - Department of Economics

Paul W. Rhode

University of North Carolina (UNC) at Chapel Hill - Department of Economics; National Bureau of Economic Research (NBER); University of Arizona

Multiple version iconThere are 3 versions of this paper

Date Written: March 5, 2016

Abstract

A growing empirical literature uses patent citations as a quality-adjusted measure for innovation, despite concerns about the validity of this measure. This paper links patents with objective measures of improvements in the quality of patented inventions – measured through performance in field trials for hybrid corn – to examine three potential factors that influence citations: 1) improvements in performance 2) citing practices of patent attorneys, and 3) citing practices of patent examiners. This analysis reveals that citations are robustly correlated with performance, which confirms that citations are a useful quality-adjusted measure for innovation. The citing practices of patent attorneys and examiners, however, also influence citations. Patent attorneys cite early patents, which help establish the patentability of an invention; this practice may inflate citation counts for early patents, particularly for inventions that have only recently become patentable. Attorneys also add self-citations; our analysis indicates that that self-citations can be an indicator of follow-on invention. By comparison, examiner-added citations are typically unrelated to improvements in performance or follow-on invention.

Keywords: innovation, patents, intellectual property, hybrid corn

JEL Classification: O30, O31, O33, O34, L70, Q10

Suggested Citation

Moser, Petra and Ohmstedt, Joerg and Rhode, Paul W., Patent Citations - An Analysis of Quality Differences and Citing Practices in Hybrid Corn (March 5, 2016). Available at SSRN: https://ssrn.com/abstract=1888191 or http://dx.doi.org/10.2139/ssrn.1888191

Petra Moser (Contact Author)

Leonard N. Stern School of Business - Department of Economics ( email )

269 Mercer Street
New York, NY 10003
United States

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Joerg Ohmstedt

Bain & Company ( email )

Two Copley Place
Boston, MA 02118
United States

Cornell University - Department of Economics ( email )

414 Uris Hall
Ithaca, NY 14853-7601
United States

Paul W. Rhode

University of North Carolina (UNC) at Chapel Hill - Department of Economics ( email )

Chapel Hill, NC 27599
United States

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

University of Arizona

Tucson, AZ 85721
United States

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