MELA_ALL prediction and the scaling relation analysis of SPIDER. Left panel: result of applying MELA_ALL on SPIDER with four features (g, r, M_⋆, σ) and missing the r_1/2. The green circle is the median value for a given x-axis bin, where the bin size is 0.1 dex. The orange line represents the linear fit of the blue data points. Right panel: M_⋆-r_1/2 relation of nETGs and SPIDER. A linear fit line is displayed for both data points. The best linear fit of the SPIDER sample is determined by averaging the linear fit using log M_⋆ and log r_1/2 as independent variables. This approach compensates for the more unbalanced distribution observed towards log M_⋆/M_⊙ ≲ 11.2. Completeness effects on the M_⋆-r_1/2 relation are not considered here, as the focus is on understanding the origin of the tilt in the predictions (left panel).