A recent decision from the U.S. Court of Appeals for the Federal Circuit serves as an important reminder that those rules of evidence you studied during law school can prove critically important, including in connection with infringement issues in software patent litigation. In Wi-LAN v. Sharp Electronics, No. 1:15-cv-00379-LPS (Fed. Cir. April 6, 2021), the Federal Circuit affirmed a Delaware district court’s ruling that the patentee’s infringement evidence, which purported to contain the source code necessary to prove the defendant’s infringement, was inadmissible because it contained hearsay and did not fall within the business record exception.

The decision is a reminder for both patent holders and accused infringers regarding the proofs that may be necessary in order to admit into evidence source code which, in software cases, can frequently be a critical part of the evidence—both at trial, and even before that as part of summary judgment motions.

The Rule Against Hearsay