Distribution of positional matches within a 10 arcmin radius in the richness-M_SZ plane. The red points in the upper panel represent the highest richness match, blue the second (when present) and green points the third-ranked richness match (when present). The mean scaling law from Rozo et al. (2015) is shown as the solid line, with the dashed lines delineating the ± 3σ band. In the lower panel, we show the distribution of these points relative to the mean relation, normalized to the logarithmic scatter. The red, blue and green histograms refer to the first-, second-, and third-ranked matches, respectively.