Unclear and Unconvincing:
How a misunderstanding led to
the heightened evidentiary requirement in patent litigation

Lee Hollaar and John Knight
School of Computing
University of Utah

Download the paper in PDF

Clear and convincing evidence is the current standard of proof necessary to invalidate an issued patent. Not only is the wholesale application of clear and convincing evidence to all forms of invalidity determination, even when the evidence has not been considered by the examiner disturbing from the standpoints of logic and basic fairness, it also appears to have come about largely through overextending an early Supreme Court decision, with little justification given.

This paper reviews how the "clear and convincing" evidentiary standard came about, and finds its development anything but clear and convincing. It looks at the problems caused, including making it easier for "patent trolls" to scare legitimate companies with dubious patents. It suggests an alternative evidentiary standard, giving deference only to the fact-finding made by the Patent Office, and indicates how will promote sound policy objectives.

This paper is one of two papers that form the basis for Professor Hollaar's amicus brief to the Supreme Court in the KSR v. Teleflex patent case. The second is also by his research assistant, John Knight: "The Motivation for the Federal Circuit Test."

The August 25, 2006, and September 23, 2006 versions of the paper is still available.

This page was last revised on May 21, 2007.

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