How the Federal Circuit’s ‘Particularized Testimony’ Rule Further Threatens the Doctrine of Equivalents


by Dennis Crouch

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The Supreme Court recently received a petition for certiorari from NexStep, Inc., challenging a Federal Circuit decision that epitomizes a four-decades-long trend of restricting the doctrine of equivalents (DOE). The petition in NexStep, Inc. v. Comcast Cable Communications, LLC (No. 24-1137), presents a fundamental question: Has the Federal Circuit improperly shackled the doctrine of equivalents with rigid, formulaic requirements contrary to Supreme Court precedent?  More particularly, the petition asks: “Whether a patentee must in every case present ‘particularized testimony and linking argument’ to establish infringement under the doctrine of equivalents.”

The case also has a nice baseball analogy.  The patent requires a “single action” performed by a user, and the accused device needs three button pushes.  The patentee’s expert, when presenting the DOE case to the jury, used a baseball pitcher analogy – recognizing that throwing a ball includes numerous small steps to accomplish the single action of throwing.  The argument here, which the jury agreed was meritorious, is that the three button pushes – while not literally the same as a single action – was the equivalent and thus infringing.  The Federal Circuit wanted more – holding that the jury did not have enough evidence to reach that conclusion.


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