“Void demographics” refers to the observed sizes, shapes, and abundance of cosmic voids—large underdense regions in the galaxy distribution—and how these statistics compare to predictions from ΛCDM simulations (Ryden 1995; Platen et al. 2007). While ΛCDM can qualitatively reproduce a foam-like pattern of voids and filaments, detailed surveys find tensions in the number of large, nearly empty voids, their sharp edges, and their environmental dependence, with some analyses suggesting that real voids are emptier, larger, or more numerous than standard Gaussian initial conditions and dark-matter–only simulations typically produce without fine-tuning feedback or bias prescriptions (Tavasoli et al. 2013; Sutter et al. 2014).