Applicant and Examiner Citations in US Patents: An Overview and Analysis

43 Pages Posted: 25 Sep 2008

See all articles by Juan Alcacer

Juan Alcacer

Harvard University - Strategy Unit

Michelle Gittelman

Rutgers, The State University of New Jersey - Rutgers University, Newark

Bhaven N. Sampat

Columbia University - Mailman School of Public Health

Date Written: August 15, 2008

Abstract

Researchers studying innovation increasingly use indicators based on patent citations. However, it is well known that not all citations originate from applicants - patent examiners contribute to citations listed in issued patents - and that this could complicate interpretation of findings in this literature. In 2001 the US Patent and Trademark Office (USPTO) began reporting examiner and applicant citations separately. In this paper, we analyze the prior art citations of all patents granted by the USPTO in 2001-2003. We show that examiner citations account for 63 per cent of all citations on the average patent, and that 40 per cent of patents have all citations added by examiners. We use multivariate regression and analysis of variance to identify the determinants of examiner shares. Examiner shares are highest for non-US applicants and in electronics, communications, and computer-related fields. However, most of the variation is explained by firm-specific variables, with the largest patent applicants having high examiner shares. Moreover, a large number of firms are granted patents that contain no applicant prior art. Taken together, our findings suggest that heterogeneity in firm-level patenting practices, in particular by high-volume applicants, has a strong influence on the data. This suggests that analysis of firm-level differences in patenting strategies is an important topic for future research.

Keywords: Technology, patents, patent examiners, prior art, citations

Suggested Citation

Alcacer, Juan and Gittelman, Michelle and Sampat, Bhaven N., Applicant and Examiner Citations in US Patents: An Overview and Analysis (August 15, 2008). Harvard Business School Strategy Unit Working Paper No. 09-016. Available at SSRN: https://ssrn.com/abstract=1273016 or http://dx.doi.org/10.2139/ssrn.1273016

Juan Alcacer (Contact Author)

Harvard University - Strategy Unit ( email )

Harvard Business School
Soldiers Field Road
Boston, MA 02163
United States
617 495-6338 (Phone)
617 495-0355 (Fax)

Michelle Gittelman

Rutgers, The State University of New Jersey - Rutgers University, Newark ( email )

180 University Avenue
Newark, NJ 07102
United States

Bhaven N. Sampat

Columbia University - Mailman School of Public Health ( email )

600 West 168th St. 6th Floor
New York, NY 10032
United States

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