Applicant and examiner citations in U.S. patents: An overview and analysis
Prior art patent citations have become a popular measure of patent quality and knowledge flow between firms. Interpreting these measurements is complicated, in some cases, because prior art citations are added by patent examiners as well as by patent applicants. The U.S. Patent and Trademark Office (USPTO) adopted new reporting procedures in 2001, making it possible to measure examiner and applicant citations separately for the first time. We analyzed prior art citations listed in all U.S. patents granted in 2001-2003, and found that examiners played a significant role in identifying prior art, adding 63% of citations on the average patent, and all citations on 40% of patents granted. An analysis of variance found that firm-specific variables explain most of the variation in examiner-citation shares. Using multivariate regression, we found that foreign applicants to the USPTO had the highest proportion of citations added by examiners. High-volume patent applicants had a greater proportion of examiner citations, and a substantial number of firms won patents without listing a single applicant citation. In terms of technology, we found higher examiner shares among patents in electronics, communications, and computer-related fields. Taken together, our findings suggest that firm-level patenting practices, particularly among high-volume applicants, have a strong influence on citation data and merit additional research.
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Schneider, Cédric, 2007. "The Determinants of Patent Applications Outcomes - Does Experience Matter?," MPRA Paper 3359, University Library of Munich, Germany.
- Papke, Leslie E & Wooldridge, Jeffrey M, 1996.
"Econometric Methods for Fractional Response Variables with an Application to 401(K) Plan Participation Rates,"
Journal of Applied Econometrics,
John Wiley & Sons, Ltd., vol. 11(6), pages 619-32, Nov.-Dec..
- Leslie E. Papke & Jeffrey M. Wooldridge, 1993. "Econometric Methods for Fractional Response Variables with an Application to 401(k) Plan Participation Rates," NBER Technical Working Papers 0147, National Bureau of Economic Research, Inc.
- Wesley M. Cohen & Richard R. Nelson & John P. Walsh, 2000.
"Protecting Their Intellectual Assets: Appropriability Conditions and Why U.S. Manufacturing Firms Patent (or Not),"
NBER Working Papers
7552, National Bureau of Economic Research, Inc.
- Wesley M Cohen & Richard R Nelson & John P Walsh, 2003. "Protecting Their Intellectual Assets: Appropriability Conditions and Why U.S. Manufacturing Firms Patent (Or Not)," Levine's Working Paper Archive 618897000000000624, David K. Levine.
- Lerner, Josh, 1995. "Patenting in the Shadow of Competitors," Journal of Law and Economics, University of Chicago Press, vol. 38(2), pages 463-95, October.
- Popp David & Juhl Ted & Johnson Daniel K.N., 2004. "Time In Purgatory: Examining the Grant Lag for U.S. Patent Applications," The B.E. Journal of Economic Analysis & Policy, De Gruyter, vol. 4(1), pages 1-45, November.
- Manuel Trajtenberg & Adam B. Jaffe & Michael S. Fogarty, 2000. "Knowledge Spillovers and Patent Citations: Evidence from a Survey of Inventors," American Economic Review, American Economic Association, vol. 90(2), pages 215-218, May.
When requesting a correction, please mention this item's handle: RePEc:eee:respol:v:38:y:2009:i:2:p:415-427. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Zhang, Lei)
If references are entirely missing, you can add them using this form.