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What Close Cases and Reversals Reveal about Claim Construction at the Federal Circuit

46 Pages Posted: 28 Apr 2013 Last revised: 6 May 2013

Thomas W. Krause

Georgetown University Law Center

Heather Auyang

Partner at Lee Tran & Liang LLP

Date Written: April 28, 2013


While most empirical studies of claim construction in the Federal Circuit focus on the set of all Federal Circuit claim construction cases, Professor Krause and Ms. Auyang focus on two revealing subsets of cases: cases involving dissents (“close cases”) and cases in which the Federal Circuit reverses the district court (“reversals”). This focus brings results-affecting differences in approach among the judges to light. The close cases data show a wide disparity among the Federal Circuit judges in terms of how likely they are to adopt a broadening (as opposed to a narrowing) claim construction, with some judges showing a “broadening rate” of over 90%, and some judges showing a narrowing rate of over 80%. The close cases data also shows how factors like “pro-patent” and “pro-affirm” vary widely across the judges. Until the Federal Circuit recognizes these internal differences and eradicates them, claim construction will continue to be panel dependent and unpredictable.

The reversals data shows that district courts consistently vote in a narrowing direction, and, more specifically, in a direction that, much more often than not, enables them to dispose of cases on summary judgment. This tendency argues strongly against any proposals for broad deference for district courts in claim construction.

The authors argue that the Federal Circuit judges should seek to understand the differences between each other within the court, and work to promote a single unified approach. As a teaching tool for district courts -- and to help keep track of where differences in approach exist -- the authors recommend that the Federal Circuit adopt a simple algorithm for claim construction cases, and they provide one such example of an algorithm.

Keywords: claim construction, patent, Federal Circuit

Suggested Citation

Krause, Thomas W. and Auyang, Heather, What Close Cases and Reversals Reveal about Claim Construction at the Federal Circuit (April 28, 2013). Available at SSRN: or

Thomas W. Krause (Contact Author)

Georgetown University Law Center ( email )

600 New Jersey Avenue, NW
Washington, DC 20001
United States

Heather Auyang

Partner at Lee Tran & Liang LLP ( email )

CA 94080
United States


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