Centred ζ-metric, or ζ_c-metric, values in km s⁻¹ as a function of the halo mass. It measures the difference between the simulated and observed lines of sight that include the halos or clusters. Halos that are replicas of the observed clusters, named at the top of each panel, serve as a reference for the shift in the distance of the other halos. The filled red circles give the ζ metric value obtained for the replicas. The higher ζ_c is, the more different the lines of sight are.