Claim Differentiation Cannot Be Used To Broaden Narrowly Described Invention

The US Court of Appeals for the Federal Circuit reversed a district court's claim construction, finding that later-added dependent claims cannot broaden claim scope affirmatively limited by the specification. Cave Consulting Grp., LLC v. Optuminsight, Inc., Case No. 17-1060 (Fed. Cir., Mar. 21, 2018) (Lourie, J). 

Cave owns a patent directed to a method for measuring physician efficiency and patient health risk stratification. The patent describes that a physician's efficiency can be determined by calculating "weighted episode of care statistics" of a peer group and of a physician. The patent explains that the invention "uses an indirect standardization technique for weighing together the episodes within the core group of medical conditions." After Cave sued Optum for infringement, Optum argued that the term "weighted episode of care statistics" should be construed to exclude direct standardization, while Cave argued for a broader claim scope that includes both