Impact of shear-richness covariance on scaling relation parameter estimation. Left: Posterior distribution of the scaling relation parameters with (dashed blue) and without (filled blue) the shear-richness covariance correction in Eq. (35), considering true source galaxy redshifts. The red (resp. black) unfilled contours are obtained considering the shear-richness covariance and using FlexZBoost (resp. BPZ) photometric redshifts for source galaxies. Right: The blue filled contours are the same as in the left panel. The purple (resp. dashed green) unfilled contours are obtained considering the shear-richness covariance and using FlexZBoost (resp. BPZ) photometric redshifts, and letting the bias (1 + b) as a free parameter. These two effects explain somewhat the low amplitude (about 1 to 10%) of the shear-richness covariance (let us note that the ln(10)β₁/μ_m factor in Eq. (35) is the order of unity; it does not change our conclusions).