Top panel: evolution of the measured σ_NMAD as a function of limiting magnitude. The solid line shows the results for our combined algorithm. The other lines show the measured σ_NMAD for QPz (dotted), the best estimate from SQUEZE (dashed), i.e. Z_SQUEZE_0, and LePhare (dash-dotted). The bottom panel shows the fraction of outliers, i.e. objects with |Δz|/(1 + z_true) > 0.15, also as a function of limiting magnitude. We can see that, while the recovered σ_NMAD for the combined algorithm is sometimes larger than that of QPz, this is compensated by a decrease in the outlier fraction.