Patent Examiner Specialization

38 Pages Posted: 11 Apr 2017 Last revised: 30 Sep 2017

See all articles by Cesare Righi

Cesare Righi

Universitat Pompeu Fabra; Barcelona Graduate School of Economics

Timothy Simcoe

Boston University - Questrom School of Business; NBER

Multiple version iconThere are 2 versions of this paper

Date Written: September 27, 2017


We study the matching of patent applications to examiners at the U.S. Patent and Trademark Office. Using test statistics originally developed to identify industry agglomeration, we find strong evidence that examiners specialize in particular technologies, even within relatively homogeneous art units. Examiner specialization is more pronounced in the biotechnology and chemistry fields, and less in computers and software. Evidence of specialization becomes weaker, but does not completely disappear, if we condition on technology sub-classes. There is no evidence that certain examiners specialize in applications that have greater importance or broader claims. More specialized examiners have a lower grant rate and produce a larger narrowing of claim-scope during the examination process. We discuss implications for instrumental variables based on examiner characteristics.

Keywords: Patent, specialization, examination, agglomeration

JEL Classification: O34, O38, K11

Suggested Citation

Righi, Cesare and Simcoe, Timothy S., Patent Examiner Specialization (September 27, 2017). Boston University Questrom School of Business Research Paper, Available at SSRN: or

Cesare Righi

Universitat Pompeu Fabra ( email )

Carrer de Ramon Trias Fargas 25-27
Jaume I building, room 20.1E34
Barcelona, 08005


Barcelona Graduate School of Economics ( email )


Timothy S. Simcoe (Contact Author)

Boston University - Questrom School of Business ( email )

595 Commonwealth Avenue
Boston, MA MA 02215
United States

NBER ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Abstract Views
PlumX Metrics