Comparison between the photo-z provided by MUFFIT (z_phot) and their spectroscopic values (z_spec) for 576 shared quiescent galaxies. Left panel: one-to-one comparison of redshifts, where dashed black line is the one-to-one relation. Top right: histogram of values Δz/(1 + z_spec), along with the Gaussian that best fits this distribution (red solid line) and the photo-z accuracy estimators defined in the text (Eqs. (5)–(7)). Bottom right: differences Δz/(1 + z_spec) as a function of the spectroscopic redshift (X-axis). The shaded region illustrates the 3 × σ_NMAD uncertainty.