Inter Partes Review: An Early Look at the Numbers

University of Chicago Law Review Dialogue, Vol. 81, p. 93, 2014

15 Pages Posted: 22 Oct 2014 Last revised: 21 Nov 2014

See all articles by Brian J. Love

Brian J. Love

Santa Clara University - School of Law

Shawn Ambwani

Unified Patents, Inc.

Date Written: October 20, 2014


In the roughly two years since inter partes review replaced inter partes reexamination, petitioners have filed almost two-thousand requests for the Patent Trial and Appeal Board to review the validity of issued U.S. patents. As partial data on inter partes review (IPR) has trickled out via the blogosphere, interest from patent practitioners and judges has grown to a fever (and sometimes fevered) pitch. To date, however, no commentator has collected a comprehensive set of statistics on IPR. Moreover, what little data currently exists focuses on overall institution and invalidation rates — data that, alone, gives us little idea whether IPR is thus far accomplishing its original goal of serving as a quick, efficient alternative to defending patent suits filed in federal court, particularly those initiated by non-practicing entities (NPEs).

This Essay aims to fill both gaps by reporting the findings of an empirical study tracking the outcome of IPRs and their impact on co-pending litigation. As described in greater detail below, we find that: Petitions for IPR are instituted for at least one challenged claim 84 percent of the time; Among instituted IPRs, all challenged claims are instituted 74 percent of the time; Among IPRs that reach a final decision on the merits, all instituted claims are invalidated or disclaimed more than 77 percent of the time; IPRs challenging NPE-owned patents are more likely to be instituted and, on average, are instituted for a larger share of challenged claims, but have their claims invalidated at a lower rate; Litigation proceeding in parallel with an instituted IPR is stayed about 82 percent of the time.

Though it is too early to draw sweeping conclusions from these statistics, they suggest that inter partes review promises to be considerably more potent than inter partes reexamination and, moreover, to have a substantial impact on co-pending patent litigation, particularly suits filed by NPEs.

Keywords: inter partes review, IPR, inter partes reexamination, America Invents Act, AIA, non-practicing entity, NPE

JEL Classification: K41, O34

Suggested Citation

Love, Brian J. and Ambwani, Shawn, Inter Partes Review: An Early Look at the Numbers (October 20, 2014). University of Chicago Law Review Dialogue, Vol. 81, p. 93, 2014, Available at SSRN:

Brian J. Love (Contact Author)

Santa Clara University - School of Law ( email )

500 El Camino Real
Santa Clara, CA 95053
United States

Shawn Ambwani

Unified Patents, Inc. ( email )

171 Main St. #106
Los Altos, CA 94022
United States

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