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Appendix B. Relationship between model complexity (expressed as model df) and mean test AUC.

FIG. B1. Relationship between model complexity (expressed as model df) and mean test AUC. Across the three model types, a significant relationship is visible (solid line; without the extreme GAM data point: AUCpred = 0.80004 – 0.00086*df, r = –0.461, P < 0.001; including the extreme data point reduces the slope to –0.00068, r = –0.376, P < 0.001), while for each model type in itself no significant pattern emerged (dark, medium, and light gray dots and lines represent GLM, GAM, and ANN, respectively). Mean numbers of model parameters are: GLM: 8.2±0.55, GAM: 50.0±3.09, and ANN: 54.9±2.94.