The failure of deposited structures in the Protein Data Bank (PDB) to represent the underlying experimental conformational and compositional heterogeneity is partly attributable to the complexity of modeling in the presence of limited signal-to-noise . Noise arises from many sources, including crystal imperfections and radiation damage in X-ray crystallography , beam-induced motion, and imperfect detector quantum efficiency (DQE) in cryo-EM . Additionally, poor modeling resulting from inaccurate phases (for X-ray) and errors in particle alignment and classification (for cryoEM) dominate the imperfect agreement between experiment and model. Further complicating the discovery of heterogeneity is that conformational heterogeneity manifests in many forms. A high amount of harmonic heterogeneity manifests in a fall off of density from a mean atomic position. This type of heterogeneity can be modeled in the PDB format by isotropic, anisotropic, or grouped (e.g. Translation-Libration-Screw ) B-factors that fit the extent of the disorder .