Effect of varying the four intrinsic scatters of our model, σ_{M⋆ − Mh}, σ_c − M, σ_fj, σ_λ, on the Spearman correlation coefficient of the residuals of the TF versus MS. Each curve was computed by varying only one scatter at a time, while leaving the others fixed to their fiducial values. The grey band shows the 1-σ uncertainty (estimated with a bootstrap) of the correlation of the observed residuals of the TF vs. MS in SPARC.