Comparison of bar sizes measured by Fourier decomposition (x-axis) and ellipse fitting (y-axis) for TNG50 (left panel) and TNG100 (right panel). For TNG50, bar sizes obtained from ellipse fitting include the original R₈₅ (blue points) and the adjusted R_85, new (red points). The gray dashed lines represent the 1:1 reference lines in both panels. The confusion matrix in the top left corner of each panel compares the number of bars identified by Fourier decomposition and ellipse fitting. Points in the plot represent galaxies identified as barred by both methods.