Table 1

Discrimination and calibration statistics from published predicted probability algorithms

	All			22–27 weeks			28–32 weeks
	CRIB	CRIB II	CRIB II_(−T)	CRIB	CRIB II	CRIB II_(−T)	CRIB	CRIB II	CRIB II_(−T)
Observed deaths, n (%)		317 (9.7)			259 (35.8)			58 (2.3)
Predicted deaths, n (%)	324.4 (9.9)	255.2 (7.8)	216.6* (6.6)	205.8 (28.4)	206.0 (28.4)	175.6* (24.2)	118.6 (4.7)	49.2 (1.9)	41.1* (1.6)
Brier score	0.052	0.055	0.057	0.163	0.174	0.183	0.020	0.021	0.021
Spiegelhalter’s z-score	p = 0.8	p = 0.003	p<0.001	p<0.001	p = 0.004	p<0.001	p = 1.00	p = 0.09	p = 0.004
AUC	0.920	0.921	0.923	0.830	0.807	0.811	0.839	0.826	0.833
Calibration-in-the-small	0.0002	0.0018	0.0044	0.0084	0.0114	0.0228	0.0014	0.0001	0.0002
Calibration-in-the-large	<0.0001	0.0004	0.0009	0.0054	0.0054	0.0133	0.0006	<0.0001	<0.0001
Cox’s regression:
Intercept α (SE)	0.08 (0.11)	0.50 (0.11)	0.91 (0.13)	0.34 (0.12)	0.52 (0.12)	0.94 (0.15)	−0.86 (0.23)	0.24 (0.39)	0.80 (0.44)
Slope β (SE)	1.08 (0.05)	1.08 (0.05)	1.16 (0.05)	0.78 (0.06)	1.08 (0.09)	1.20 (0.10)	1.02 (0.09)	1.02 (0.11)	1.13 (0.12)
Test: α = 0, β = 1	p = 0.2	p<0.001	p<0.001	p<0.001	p<0.001	p<0.001	p<0.001	p = 0.4	p = 0.02
Test: α = 0 \| β = 1	p = 0.6	p<0.001	p<0.001	p<0.001	p<0.001	p<0.001	p<0.001	p = 0.2	p = 0.01
Test: β = 1 \| α	p = 0.1	p = 0.08	p = 0.002	p = 0.0007	p = 0.4	p = 0.04	p = 0.8	p = 0.9	p = 0.3

*Calculated using published predictive algorithm for CRIB II.
AUC, area under the curve; CRIB, Clinical Risk Index for Babies; CRIB II_(−T), CRIB II without temperature at admission.