Mean differences between photometric and spectroscopic redshifts. Left: mean differences of (z_phot − z_spec)/(1 + z_spec) of non-catastrophic failures in bins of z_spec as a function of z_spec for Flag ≥ 3 redshifts released by the C3R2 project: yellow from Masters et al. (2015, 2017, 2019); magenta from G2020; red from Euclid Collaboration (2021); blue, this paper. The black line shows the average in bins of the whole sample, the dotted lines the error range. Right: same, but for Flag = 4 redshifts.