Unsupported Expert Testimony Cannot Create a Genuine Issue of Material Fact

Written by: Ariadad Fattahyani and Nathan D. Reeves

MIRROR WORLDS TECHS., LLC v. META PLATFORMS, INC.

Before Prost, Taranto, and Stark. Appeal from the United States District Court for the Southern District of New York.

Summary: Expert testimony that is conclusory, supported by inadmissible evidence, or fails to address key claim limitations does not suffice to create a genuine issue of material fact sufficient to avoid summary judgment of non-infringement.

Mirror Worlds alleged that Meta’s backend systems infringed several patents covering stream-based data organization. After the close of discovery, Meta moved for summary judgment of non-infringement, arguing that its systems did not meet various claim limitations regarding sources of data and how data was presented. The district court granted summary judgment of non-infringement, agreeing with Meta that Mirror Worlds had not presented evidence sufficient to show that Meta’s systems practiced each limitation of the asserted claims. Mirror Worlds appealed, arguing that the district court overlooked its expert’s testimony, which it alleged created a genuine issue of material fact sufficient to avoid summary judgment.

The Federal Circuit upheld the district court’s findings, agreeing that Mirror Worlds had not produced sufficient evidence to create genuine disputes of material fact. In particular, the Court noted that Mirror Worlds’s expert improperly relied on inadmissible, unauthenticated screenshots created by a third party; that other aspects of the expert’s testimony were conclusory; and that the expert failed to address the full scope of each claim limitation. The Federal Circuit held that such testimony was not sufficient to create a genuine issue of material fact.

Editor: Sean Murray