Sanity check of classifier performance as a function of observational regime. Receiver operating characteristic (ROC) curves for the spiral vs. smooth classifier evaluated in bins of (a) apparent size, using the Petrosian radius (arcsec), and (b) r band Petrosian magnitude. Curves show the mean ROC across cross-validation folds, with shaded regions indicating the ±1σ scatter between folds; the corresponding AUC values (mean ± standard deviation) are listed in the legend for each bin. Performance remains high across the full range, with the expected mild degradation toward the smallest, and faintest galaxies where morphology measurements are noisier and resolution is lower.