2. Calibration plot of predictive model from development set (n=1,112): predicted probability vs. actual morbidity. The 45-degree dotted line is the ideal prediction curve, indicating 100% predictive power. The apparent line represents the actual prediction ability of the nomogram; it fluctuates above and below the ideal curve, which indicates a medium prediction ability. The bias-corrected line is obtained after correcting overfitting of the apparent line. The closer they are, the less likely that overfitting is present.