Distribution of the fraction of galaxies with |Δz| < z_err as a function of z_err (grey histogram). The horizontal line marks a fraction of 68% expected if z_err estimates are accurate. Small dots indicate the z_err and |Δz| of individual galaxies (right scale). The dots are orange and green for |Δz| > z_err and |Δz| < z_err, respectively. The dotted red line marks the expected σ_NMAD as a function of z_err, while the connected dark blue squares with error bars indicate the observed σ_NMAD and the 16–84th percentiles of its confidence interval.