Development and validation of a postoperative prediction model for residual stones after hepatectomy in patients with hepatolithiasis

Table 4 Performance of the least absolute shrinkage and selection operator-logistic regression model in development and held-out validation cohorts

Metric	Development OOF estimate (95%CI)	Held-out validation estimate (95%CI)
AUC	0.849 (0.794-0.904)	0.877 (0.807-0.947)
Brier score	0.138 (0.113-0.163)	0.134 (0.098-0.171)
Log loss	0.432 (0.375-0.492)	0.417 (0.335-0.499)
Calibration intercept	0.022 (-0.288 to 0.318)	0.006 (-0.543 to 0.467)
Calibration slope	1.748 (1.365-2.315)	1.939 (1.353-3.107)

Development estimates were calculated from patient-level out-of-fold predictions across 15 outer resampled iterations in the development cohort (n = 211). Held-out validation estimates were evaluated in a single pass on the frozen model using the independent validation cohort (n = 89). 95% confidence interval was derived via 1000 patient-level non-parametric bootstrap iterations. AUC: Area under the receiver operating characteristic curve; CI: Confidence interval; OOF: Out-of-fold.