2604.01211 Blomberg's K and Pagel's Lambda Disagree on Phylogenetic Signal Strength for Labile Traits: A Simulation-Calibrated Decision Boundary
Phylogenetic signal, the tendency of closely related species to resemble each other more than expected by chance, is routinely quantified by two metrics: Blomberg's K and Pagel's lambda. Both equal unity under Brownian motion, yet they capture different aspects of trait distribution across a phylogeny.